Celestron 11055 Users Manual

11055 Ci700a

11065 55351133-35a9-4256-bbe5-0ab873b6c579

91525 to the manual 55351133-35a9-4256-bbe5-0ab873b6c579

2015-02-02

: Celestron Celestron-11055-Users-Manual-393274 celestron-11055-users-manual-393274 celestron pdf

Open the PDF directly: View PDF .
Page Count: 80

INTRODUCTION
ASSEMBLING YOUR CM-1100
TELESCOPE BASICS
ASTRONOMY BASICS
USING THE DRIVE
CELESTIAL OBSERVING
CELESTIAL PHOTOGRAPHY
- CCD Imaging
TELESCOPE MAINTENANCE
- Collimation
OPTIONAL ACCESSORIES
THE MESSIER CATALOG
BRIGHT STAR LIST
FURTHER READING

CELESTRON CI-700 / CM-1100 / CM-1400

INSTRUCTION MANUAL

Models #91525 / #11055 / #11065

ii • Table of Contents

The Celestron CM-1100/1400

Celestron International

2835 Columbia Street

Torrance, CA 90503

(310) 328-9560

No part of this manual may be reproduced in any form or by any means, electronic or mechanical, including photocopy-

ing, recording, or by any information storage and retrieval system, without written permission from Celestron Interna-

tional.

Celestron International provides this manual “as is” without warranty of any kind, either expressed or implied, including

but not limited to the implied warranties of merchantability and fitness for a particular purpose. Celestron may make

modifications to this manual and/or the products described herein at any time without notice or obligation.

Table of Contents • iii

▲▲

▲ INTRODUCTION .................................................................................................................................. 1

How to Use this Manual..................................................................................................................... 2

A Word of Caution ............................................................................................................................. 2

The Schmidt-Cassegrain Optical System .......................................................................................... 3

▲▲

▲ ASSEMBLING YOUR CELESTRON CM-1100 ...................................................................................... 4

Unpacking Your Celestron CM-1100 .................................................................................................. 4

Setting Up the Tripod ......................................................................................................................... 6

Attaching the Center Leg Brace ........................................................................................................ 7

Attaching the Central Column ............................................................................................................ 7

Attaching the Equatorial Mount.......................................................................................................... 8

Installing the Counterweight Bar ........................................................................................................ 9

Installing the Counterweight ............................................................................................................... 9

Attaching the Celestron CM-1100 to the Mount ................................................................................10

Attaching the Visual Back ................................................................................................................11

Installing the Star Diagonal ...............................................................................................................11

Installing the Eyepiece .....................................................................................................................12

Installing the Finder ..........................................................................................................................13

Installing the Polar Axis Finder .........................................................................................................14

Moving the Telescope in R.A. and DEC ............................................................................................15

Using the Slow Motion Controls ........................................................................................................15

Adjusting the Mount .........................................................................................................................16

Balancing the Mount in R.A. .............................................................................................................17

Balancing the Mount in DEC.............................................................................................................18

Transporting Your Celestron CM-1100 ..............................................................................................19

Storing Your Celestron CM-1100 ......................................................................................................19

Technical Specifications ...................................................................................................................20

▲ ▲

▲ TELESCOPE BASICS .........................................................................................................................22

Image Orientation .............................................................................................................................22

Focusing ..........................................................................................................................................23

General Photography Hints ...............................................................................................................24

Aligning the Finder ............................................................................................................................24

Your First Look .................................................................................................................................25

Daytime Observing .....................................................................................................................25

Nighttime Observing ...................................................................................................................26

Calculating Magnification ..................................................................................................................27

Determining Field of View .................................................................................................................27

▲ ▲

▲ ASTRONOMY BASICS .......................................................................................................................28

The Celestial Coordinate System ......................................................................................................28

Motion of the Stars ...........................................................................................................................29

Polar Alignment ................................................................................................................................30

Finding the Pole ...............................................................................................................................31

Latitude Scales ..........................................................................................................................32

Pointing at Polaris ......................................................................................................................33

The Polar Axis Finder.................................................................................................................34

Declination Drift ..........................................................................................................................35

Aligning the Setting Circles .............................................................................................................36

T A B L E O F C O N T E N T S

iv • Table of Contents

▲ ▲

▲ USING THE DRIVE .............................................................................................................................37

Powering Up the Drive ......................................................................................................................37

Guide Speed ....................................................................................................................................38

Tracking Rate Selection....................................................................................................................38

BC -Backlash Correction ..................................................................................................................39

Periodic Error Correction ..................................................................................................................39

HC/CCD ...........................................................................................................................................40

12 V DC ...........................................................................................................................................40

Northern/Southern Hemisphere Operation.........................................................................................41

Using the Hand Controller .................................................................................................................41

R.A./DEC Reverse ............................................................................................................................42

Autoguiding ......................................................................................................................................42

▲ ▲

▲ CELESTIAL OBSERVING ...................................................................................................................43

Observing the Moon ..........................................................................................................................43

Observing the Planets ......................................................................................................................43

Observing the Sun ............................................................................................................................44

Observing Deep-Sky Objects ............................................................................................................45

Using the Setting Circles ...........................................................................................................45

Star Hopping ..............................................................................................................................46

Viewing Conditions ...........................................................................................................................48

Transparency .............................................................................................................................48

Sky Illumination .........................................................................................................................48

Seeing .......................................................................................................................................48

▲ ▲

▲ CELESTIAL PHOTOGRAPHY .............................................................................................................50

Short Exposure Prime Focus ...........................................................................................................51

Piggyback ........................................................................................................................................53

Eyepiece Projection .........................................................................................................................55

Long Exposure Prime Focus ............................................................................................................57

CCD Imaging ....................................................................................................................................59

Description of F-Numbers ............................................................................................................60

Fastar Configuration ...................................................................................................................60

Imaging at f/2.1 ..........................................................................................................................61

Imaging at f/7 .............................................................................................................................61

Imaging at f/11 ...........................................................................................................................61

Imaging at f/22 ...........................................................................................................................62

▲ ▲

▲ TELESCOPE MAINTENANCE .............................................................................................................63

Care and Cleaning of the Optics .......................................................................................................63

Collimation .......................................................................................................................................63

▲▲

▲ OPTIONAL ACCESSORIES ................................................................................................................66

▲▲

▲ THE MESSIER CATALOG ..................................................................................................................70

▲ ▲

▲ LIST OF BRIGHT STARS ...................................................................................................................73

▲ ▲

▲ FOR FURTHER READING ...................................................................................................................74

Introduction • 1

INTRODUCTION

Welcome to the Celestron world of amateur astronomy! For more than a

quarter of a century, Celestron has provided amateur astronomers with the

tools needed to explore the universe. The Celestron CM-1100 and CM-1400

continues in this proud tradition combining large aperture optics with ease of

use and portability. With a mirror diameter of 11 inches, your Celestron CM-

1100 has a light gathering power of 1,593 times that of the unaided human eye,

and the CM-1400 has a light gathering power of 2,581 times that of the unaided

human eye. Yet despite their large apertures, the Celestron CM-1100 and CM-

1400 optical systems are extremely compact and portable because they utilize

the Schmidt-Cassegrain design. This means you can take your Celestron CM-

1100 or CM-1400 to the mountains or desert or wherever you observe.

The Celestron CM-1100 and CM-1400 are made of the highest quality materials

to ensure stability and durability. All this adds up to telescopes that will give

you a lifetime of pleasure with a minimal amount of maintenance. And, your

Celestron CM-1100 and CM-1400 are versatile — they grow as your interest

in astronomy grows.

Your Celestron CM-1100 and CM-1400, are not limited to astronomical viewing

alone. They can also be used for terrestrial viewing to study the world around

you. All you need to do is take the time to familiarize yourself with your

Celestron telescope and its operation.

NOTE

The CM-1100 and CM-1400 share the same mount and are basically the

same with the exception of the larger aperture of the 14". So, this

manual will basically discuss the CM-1100 but will discuss the CM-1400

when there are differences. Users of the CI-700 mount by itself will find

complete assembly and operation instructions in the "AssemblingYour

CM-1100" and "Using the Drive" sections of this manual.

2 • Introduction

This manual is designed to instruct you in the proper use of your Celestron

CM-1100 telescope. The instructions are for assembly, initial use, long term

operation, and maintenance. There are seven major sections to the manual.

The first section covers the proper procedure for setting up your Celestron CM-

1100 telescope. This includes setting up the tripod, attaching the telescope to

the mount, balancing the telescope, etc.

The second section deals with the basics of telescope use. Topics include

focusing, aligning the finder, and taking your first look. The third section

deals with the basics of astronomy which includes the celestial coordinate

system, the motion of the stars, and polar alignment. The fourth section deals

with celestial observing covering visual observations of the planets and deep-

sky objects. Using both the setting circles and star hopping are discussed.

The fifth section covers celestial photography working from the easiest to the

most difficult. The last major section is on telescope maintenance, specifically

on cleaning and collimation. Keeping your CM-1100 in proper collimation

is the single most important thing you can do to ensure it performs well.

In addition to the major sections mentioned previously, there is a list of optional

accessories for your Celestron CM-1100 that include a brief description of its

purpose. This is the section to consult when you’ve mastered the basics and

are ready for new, more challenging observations. The final part of this manual

contains a list of objects that can be observed through your Celestron CM-1100

telescope. Included are the coordinates for each object, its brightness, and a

code which indicates what type of an object it is. In addition, there is a list of

bright stars used for aligning the setting circles.

Read the assembly instructions through completely before you attempt to set

up your Celestron CM-1100 telescope. Then, once you’ve set up your

Celestron CM-1100, read the section on “Telescope Basics” before you take it

outside and use it. This will ensure that you are familiar with your telescope

before you try to use it under a dark sky. Since it will take a few observing

sessions to familiarize yourself with your Celestron CM-1100, you should keep

this manual handy until you have fully mastered your telescope’s operation.

After that, save the manual for future reference.

Your Celestron CM-1100 is designed to give you hours of fun and rewarding

observations. There are, however, a few things to consider before using your

telescope that will ensure your safety and protect your equipment.

WARNING ! NEVER LOOK DIRECTLY AT THE SUN WITH THE NAKED EYE OR WITH A

TELESCOPE. PERMANENT AND IRREVERSIBLE EYE DAMAGE MAY

RESULT.

NEVER USE YOUR TELESCOPE TO PROJECT AN IMAGE OF THE SUN

ONTO ANY SURFACE. INTERNAL HEAT BUILD-UP CAN DAMAGE THE

TELESCOPE AND/OR ANY ACCESSORIES ATTACHED TO IT.

NEVER USE AN EYEPIECE SOLAR FILTER OR A HERSCHEL WEDGE.

INTERNAL HEAT BUILD-UP INSIDE THE TELESCOPE CAN CAUSE THESE

DEVICES TO CRACK OR BREAK, ALLOWING UNFILTERED SUNLIGHT TO

PASS THROUGH TO THE EYE.

NEVER LEAVE THE TELESCOPE UNSUPERVISED, EITHER WHEN CHIL-

How to Use This

Manual

A Word of Caution

Introduction • 3

DREN ARE PRESENT OR ADULTS WHO MAY NOT BE FAMILIAR WITH

THE CORRECT OPERATING PROCEDURES OF YOUR TELESCOPE.

NEVER POINT YOUR TELESCOPE AT THE SUN UNLESS YOU HAVE THE

PROPER SOLAR FILTER. WHEN USING YOUR TELESCOPE WITH THE

CORRECT SOLAR FILTER, ALWAYS COVER THE FINDER. ALTHOUGH

SMALL IN APERTURE, THIS INSTRUMENT HAS ENOUGH LIGHT GATHER-

ING POWER TO CAUSE PERMANENT AND IRREVERSIBLE EYE DAMAGE.

IN ADDITION, THE IMAGE PROJECTED BY THE FINDER IS HOT ENOUGH

TO BURN SKIN OR CLOTHING.

A telescope is nothing more than an instrument that collects and focuses light.

The nature of the optical design determines how the light is focused. Some

telescopes, known as refractors, use lenses while others, known as reflectors,

use mirrors. The Schmidt-Cassegrain optical (or Schmidt-Cass for short)

system uses a combination of mirrors and lenses and is referred to as a

compound or catadioptric telescope. This unique design offers large diameter

optics while maintaining very short tube lengths, making them extremely

portable. This makes them extremely popular among amateur astronomers.

The Schmidt-Cassegrain system consists of a zero power corrector plate, a

spherical primary mirror, and a secondary mirror. Once light rays enter the

optical system, they travel the length of the optical tube three times.

Inside the optical tube you will notice a black tube (not illustrated) that extends

out from the center hole in the primary mirror. This is the primary baffle tube

which prevents stray light from passing through to the eyepiece or camera

without striking the primary or secondary mirrors.

Figure 1-1

This cross-sectional diagram shows the light path of the Schmidt-Cassegrain optical

system. Note that the light rays travel the length of the telescope tube three times,

making this a compact optical design. Note that the curve of the corrector plate is

greatly exaggerated.

The Schmidt-Cassegrain

Optical System

4 • Assembling Your CM-1100

ASSEMBLING YOUR CM-1100

This section covers the assembly instructions for your Celestron CM-1100

telescope. The Celestron CM-1100 should be set up indoors the first time so

that it is easy to identify the various parts and familiarize yourself with the

correct assembly procedure before attempting it outdoors.

The Celestron CM-1100 is a standard 11" Schmidt-Cassegrain telescope on a

heavy-duty German equatorial mount. The Celestron CM-1100 comes stan-

dard with Starbright ™ enhanced multilayer aluminum coatings on the primary

and secondary mirrors for increased reflectivity. Also, the corrector plate is

fully coated to allow maximum light transmission. The Celestron CM-1100 is

shipped in six boxes. One contains the telescope and is accompanied by a

box that contains most of the standard accessories, which are:

• 26mm Plössl Ocular 1-1/4"

• Visual Back 1-1/4" (2" Visual Back on the CM-1400)

• Star Diagonal 1-1/4" (2" Mirror Diagonal for the CM-1400)

• 9x50mm Finderscope with Bracket

• Car Battery Adapter

• Lens Cap

In separate boxes are the following:

• Optical Tube Assembly

• Equatorial Mount and Counterweight Bar

• Tripod

• Central Column, Electronics Module, Polar Axis Finder and Hand Control

• One 23 Pound Counterweight (The CM-1400 come with two 25 lb.

counterweights)

• Accessories for Optical Tube

Included is all the hardware needed to assemble the telescope.

Use the diagram on the following page (see Figure 2-1) to familiarize yourself

with the various parts of your Celestron CM-1100 telescope.

Remove all the pieces from their respective boxes and place on a flat, clear

work area. A large floor space is ideal. When setting up your Celestron CM-

1100) you must start with the tripod and work up from there. These instruc-

tions are laid out in the order each task must be performed.

Unpacking Your

Celestron CM-1100

Assembling Your CM-1100 • 5

Figure 2-1

1. Optical Tube

2. Finderscope

3. Star Diagonal

4. Eyepiece

5. Polar Axis Finderscope

6. Drive Control Electronics

7. Hand Control

8. Tripod

9. Center Leg Brace

10. Counterweight

11. Counterweight Bar

12. R.A. Clutch Knob

13. DEC Clutch Knob

14. Mounting Platform Clamp Knob

15. Dovetail Slidebar

16. Objective Lens Cover

CM-1100

6 • Assembling Your CM-1100

Setting Up the Tripod

The tripod legs attach to a central column which together form the tripod to

which the equatorial mount attaches. The tripod comes with two leg support

brackets; a collapsible one that is already attached to the lower legs and a

removable one that must be attached. To set up the tripod:

1. Stand the tripod vertically on a level surface, with the feet facing down (See

Figure 2-2).

2. Grab the lower portion of two of the tripod legs and lift them slightly off the

ground so that the tripod is resting on the third leg.

3. Extend the tripod legs by pulling the tripod legs apart until the collapsible

leg bracket is fully extended. (See Figure 2-3)

Before the tripod is ready to support the equatorial head and optical tube the

center leg support brace must first be installed.

Figure 2-2 Figure 2-3

Assembling Your CM-1100 • 7

Before the equatorial mount head can be installed, the central column with

the electronics module must be attached to the tripod. To attach the central

column:

1 Position the central column so that the electronics module is right

side up (see Figure 2-4).

2 Place the lower end of the central column over the tripod head.

3 Rotate the column until the three holes line up with the threaded

holes on the side of the tripod head. The electronics console should

be positioned directly between two of the tripod leg hinges to provide

easy access to it even when the counterweight bar and

counterweight(s) are attached.

4 Insert the three 3/8-16 button head cap screws provided through the

holes in the central column and into the tripod head.

5 Tighten the screws to hold the column securely in place.

Attaching the Center

Leg Brace For maximum rigidity, the CI 700 tripod has a center leg brace that installs on

to the threaded rod below the tripod head. This brace fits snugly against the

tripod legs, increasing stability while reducing vibration and flexure. To attach

the center leg brace:

1 Unscrew the tension knob from the threaded rod beneath the tripod

head.

2 Place the center leg brace onto the threaded rod so that the cup on

the end of each bracket contours to the curve of the tripod legs.

3 Rotate the tension knob back on the threaded rod until the brace is

very snug against each tripod leg.

Attaching the Central

Column

Center Leg Brace

Central Column

Electronics Console

Figure 2-4

8 • Assembling Your CM-1100

After the tripod is set up, you are ready to attach the equatorial mount. The

equatorial mount is the platform to which the telescope attaches and allows

you to move the telescope in right acsension and declination. The mount is

also adjustable so you can orient the axis of rotation so that it is parallel with

the Earth’s axis of rotation (see the section on “Polar Alignment”). To attach

the equatorial mount to the tripod:

1. Insert the base of the equatorial mount into the top of the central column.

2. Rotate the equatorial mount on the central column until the holes in the

mount line up with those in the central column and the dec opening (where

the counterweight shaft will go) is positioned directly over one of the tripod

legs.

3. Insert the three remaining 3/8-16 cap screws and washers provided through

the holes in the central pier and into the equatorial mount (see Figure 2-5).

4. Tighten the screws to hold the equatorial mount in place.

Attaching the

Equatorial Mount

Figure 2-5

Central Column

Equatorial Mount

Counterweight

Shaft Opening

Assembling Your CM-1100 • 9

To properly balance the telescope, the mount comes with a counterweight bar

and one counterweight (the CM-1400 comes with two counterweights). The

counterweight bar is located in the same box as the Equatorial Mount Head —

in a cutout along the bottom of the shipping box. To install the counterweight

bar:

1. Locate the opening in the equatorial mount on the DEC axis (see figure 2-

6). It is opposite the telescope mounting platform.

2. Thread the counterweight bar into the opening until tight.

Once the bar is securely in place you are ready to attach the counterweight.

Since the fully assembled telescope is quite heavy, position the mount

so that the tripod leg with the counterweight bar over it is pointing

towards north before the tube assembly and counterweights are at-

tached. This will make the polar alignment procedure much easier.

The Celestron CM-1100 comes standard with one 23 pound counterweight. The

CM-1400 comes with two 25 pound counterweights. To install the

counterweight(s):

1. Orient the mount so that the counterweight bar points toward the ground

(see figure 2-7).

2. Remove the counterweight safety thumbscrew and washer on the end of

the counterweight bar (i.e., opposite the end that attaches to the mount).

3. Loosen the set screw on the side of the counterweight.

4. Slide the counterweight onto the shaft.

5. Tighten the locking screw on the side of the weight to hold the counter-

weight in place.

6. Replace the counterweight safety thumbscrew and washer.

Installing the

Counterweight Bar

Installing the

Counterweight

HINT

Figure 2-5

Counterweight

Bar

Counterweight Bar

Safety Screw

Figure 2-6

Counterweight

Bar

Counterweight

Figure 2-7

10 • Assembling Your CM-1100

The telescope attaches to the mount via a dovetail slide bar which is mounted

along the bottom of the telescope. Before you attach the optical tube, make

sure that the declination and right ascension clutch knobs are tight. This will

ensure that the mount does not move suddenly while attaching the telescope.

To mount the telescope tube:

1 Loosen the knobs on the side of the telescope mounting platform. This

allows you to slide the dovetail bar on the telescope onto the mount.

2 Slide the dovetail bar on the telescope tube into the mounting platform of

the mount. Slide the telescope so that the back of the dovetail bar is

almost flush with the back of the mounting platform.

3 Tighten the locking knobs on the side of the mounting platform to hold the

telescope in place.

4 Slide the dovetail slide bar safety clamp down the front end of the slide bar

until it touches the mounting platform. This clamp is designed to keep the

telescope from sliding off the mount in case the knobs on the side of the

platform comes loose. It is best to wait until the telescope is balanced in

R.A. and DEC before attaching the safety clamp (see "Balancing the

Mount in DEC" later in this section).

Attaching the Optical

Tube to the Mount

Figure 2-8

Optical Tube

Dovetail Slide Bar

Mounting Platform

Locking Knobs

Assembling Your CM-1100 • 11

The visual back is the accessory that allows you to attach all visual accesso-

ries to the telescope. To attach the visual back:

1. Remove the plastic cover on the rear cell.

2. Place the knurled slip ring on the visual back over the threads on the rear

cell.

3. Hold the visual back with the set screw in a convenient position and rotate

the knurled slip ring clockwise until tight.

Once this is done, you are ready to attach other accessories, such as eye-

pieces, diagonal prisms, etc.

If you want to remove the visual back, rotate the slip ring counterclockwise until

it separates from the rear cell.

The star diagonal is a prism that diverts the light at a right angle to the light

path of the telescope. This allows you to observe in positions that are physi-

cally more comfortable than if you looked straight through. To attach the star

diagonal: NOTE: The CM-1400 uses a 2" mirror diagonal.

1. Turn the set screw on the visual back until its tip no longer extends into

(i.e., obstructs) the inner diameter of the visual back.

2. Slide the chrome portion of the star diagonal into the visual back.

3. Tighten the set screw on the visual back to hold the star diagonal in place.

If you wish to change the orientation of the star diagonal, loosen the set screw

on the visual back until the star diagonal rotates freely. Rotate the diagonal to

the desired position and tighten the set screw.

Attaching the Visual

Back

Installing the Star

Diagonal

Figure 2-9

12 • Assembling Your CM-1100

The eyepiece, or ocular, is an optical element that magnifies the image

focused by the telescope. The ocular(s) fit into either the visual back directly,

the star diagonal, or the Erect Image Diagonal (purchased separately). To

install an ocular:

1. Loosen the set screw on the star diagonal until the tip no longer extends

into the inner diameter of the eyepiece end of the diagonal.

2. Slide the chrome portion of the eyepiece into the star diagonal.

3. Tighten the set screw on the star diagonal to hold the eyepiece in place.

To remove the eyepiece, loosen the set screw on the star diagonal and slide

the eyepiece out. You can replace it with another ocular (purchased sepa-

rately).

NOTE: NOTE:

NOTE: The 2" mirror diagonal has a 1 1/4" eyepiece adapter to use 1 1/4"

eyepieces. You may remove the adapter to use 2" eyepieces.

Eyepieces are commonly referred to by focal length and barrel diameter. The

focal length of each eyepiece is printed on the eyepiece barrel. The longer the

focal length (i.e., the larger the number) the lower the eyepiece power and the

shorter the focal length (i.e., the smaller the number) the higher the magnifica-

tion. Generally, you will use low-to-moderate power when viewing. For more

information on how to determine power, see the section on “Calculating

Magnification.”

Installing the EyepieceInstalling the Eyepiece

Installing the Eyepiece

Figure 2-10Figure 2-10

Figure 2-10

Assembling Your CM-1100 • 13

The CM-1100 telescope come with a 9x50 finderscope used to help you locate

and center objects in the main field of your telescope. To accomplish this, the

finder has a built-in cross-hair reticle that shows the optical center of the

finderscope.

Start by removing the finder and hardware from the plastic wrapper. Included

are the following:

• 9x50mm Finder

• Finder Bracket

• Rubber O-ring

• Three Nylon Tipped Thumbscrews (10-24x1/2")

• Two Allen Head Screws (8-32x1/2")

To install the finder:

1. Attach the bracket to the optical tube. To do this, place the curved portion

of the bracket with the slot over the two holes in the rear cell. The bracket

should be oriented so that the rings that hold the finder are over the

telescope tube, not the rear cell (see Figure 2-1). Start threading the

screws in by hand and tighten fully with an Allen wrench.

2. Partially thread-in the three nylon-tipped thumbscrews that hold the finder

in place inside the bracket. Tighten the screws until the nylon heads are

flush with the inner diameter of the bracket ring. Do NOTNOT

NOTNOT

NOT thread them in

completely or they will interfere with the placement of the finder. (Having

the screws in place when the finder is installed will be easier than trying to

insert the screws after the finder has been installed.)

3. Slide the rubber O-ring over the back of the finder (it will NOTNOT

NOTNOT

NOT fit over the

objective end of the finder). It may need to be stretched a little. Once on

the main body of the finder, slide it up about one inch from the end of the

finder.

4. Rotate the finder until one cross hair is parallel to the R.A. axis and the

other is parallel to the DEC axis.

5. Slide the eyepiece end of the finder into the front of the bracket.

6. Slightly tighten the three nylon tipped thumbscrews on the front ring of the

bracket to hold the finder in place.

7. Once on, push the finder back until the O-ring is snug inside the back ring

of the finder bracket.

8. Hand tighten the three nylon tipped thumbscrews until snug.

Installing the FinderInstalling the Finder

Installing the Finder

14 • Assembling Your CM-1100

To aid in polar aligning the mount, your telescope comes standard with a Polar

Housing Finder. It installs directly on top of the polar housing of the mount. To

install the Polar Finder:

1. Locate the Polar Finder assembly. The Polar Finder assembly consists

of the polar finder, mounting bracket and knurled mounting screw (see

Figure 2.11).

2. Place the Polar Finder Assembly on top of the polar axis housing so that

the mounting stop on the metal bracket sits flush against the rear of the

polar housing.

3. Secure the Polar Finder Assembly to the mount by threading the Knurled

Mounting Screw into the threaded hole on top of the Polar Housing.

The Polar Axis Finder is now installed and ready to use. To learn how to polar

align the mount using the Polar Axis Finder, refer to the Astronomy Basics

section of the manual.

Installing the PolarInstalling the Polar

Installing the Polar

FinderFinder

Finder

Figure 2-11

Finderscope Bracket Assembly

Knurled Mounting Screw

Polar Axis Housing

Nylon Tension Screw

Polar Finderscope

Mounting Stop

Assembling Your CM-1100 • 15

Once set up, you need to point your telescope at various portions of the sky to

observe different objects. To make rough adjustments, loosen the R.A. and

DEC clutch knobs slightly and move the telescope in the desired direction.

Both the R.A. and DEC axis have two knobs to clutch down each axis of the

telescope. To loosen the clutches on the telescope, rotate the clutch knobs

(see figure below) counterclockwise. Once your have found your desired object

in the finderscope, rotate the clutch knobs on each axis clockwise to lock the

telescope in place.

Moving the TelescopeMoving the Telescope

Moving the Telescope

in R.A. and DECin R.A. and DEC

in R.A. and DEC

Using the Slow MotionUsing the Slow Motion

Using the Slow Motion

ControlsControls

Controls The CI 700 mount is equipped with slow motion controls on both the R.A. and

Declination axis. Each slow motion control has a clutch mechanism that

allows you to override the tracking motor and adjust the amount of tension

when turning the knob. To adjust the clutch mechanism, hold the slow motion

knob with one hand, and rotate the clutch wheel with your other hand. Rotate

the clutch wheel clockwise (downward) to increase the tension on the slow

motion control and counterclockwise (upward) to decrease the tension.

DEC Clutch Knobs

R.A. Clutch Knobs

DEC Slow Motion Control

R.A. Slow Motion Control

Slow Motion Knob

Clutch Wheel

Figure 2-12

Figure 2-13

16 • Assembling Your CM-1100

In order for the clock drive to track accurately, the telescope’s axis of rotation

must be parallel to the Earth’s axis of rotation, a process known as polar

alignment. Polar alignment is achieved NOTNOT

NOTNOT

NOT by moving the telescope in R.A.

or DEC, but by adjusting the mount vertically, which is called altitude, and

horizontally, which is called azimuth. This section simply covers the correct

movement of the telescope during the polar alignment process. The actual

process of polar alignment, that is making the telescope’s axis of rotation

parallel to the Earth’s, is described later in this manual in the section on “Polar

Alignment.”

To adjust the mount in altitude:

1. Locate the altitude adjustment bolt just above the tripod column (see

figure 2-14).

2. Using the 7/32" Allen wrench provided, turn the altitude adjustment bolt

until the mount is at the right elevation.

The total altitude range is from 13° to 65°. With the 23 lb counterweight

attached to the counterweight shaft, the equatorial head can go as low as 20°

without hitting the tripod leg.

To adjust the mount in azimuth:

1. Locate the azimuth adjustment bolt on the flat portion of the tripod column.

2. Loosen the two azimuth lock knobs located on the top of the tripod

column.

3. Turn the azimuth adjustment bolt with the 7/32" Allen wrench until the

polar axis is pointing in the right direction.

4. Tighten the azimuth lock knobs to hold the mount in place.

The mount can be moved ± 7° in azimuth using these bolts.

Keep in mind that adjusting the mount is done during the polar alignment

process only. Once polar aligned, the mount must NOTNOT

NOTNOT

NOT be moved. Pointing

the telescope is done by moving the mount in right ascension and declination,

as described earlier in this manual. Once the appropriate adjustments have

been made and you are aligned on the celestial pole, turn the clock drive on

and the telescope will track.

Adjusting the MountAdjusting the Mount

Adjusting the Mount

Figure 2-14

Altitude Adjustment Bolt

Azimuth Adjustment Bolt

Bubble Level

Azimuth Lock Screws

Assembling Your CM-1100 • 17

To eliminate undue stress on the mount, the telescope should be properly

balanced around the polar axis. Proper balancing is crucial for accurate

tracking. To balance the mount:

1. Verify that the telescope securing knobs on the telescope mounting

platform are tight.

2. Loosen the R.A. clutch knobs and position the telescope off to one side of

the mount. The counterweight bar will extend horizontally on the opposite

side of the mount.

3. Release the telescope — GRADUALLYGRADUALLY

GRADUALLYGRADUALLY

GRADUALLY — to see which way the telescope

“rolls.”

4. Loosen the set screws on the side of the counterweight so it can be moved

the length of the counterweight bar.

5. Move the counterweight to a point where it balances the telescope (i.e.,

the telescope remains stationary when the R.A. clutch knobs are loose).

6. Tighten the set screw on the counterweight to hold it in place.

While the above instructions describe a perfect balance arrangement, there

should be a SLIGHTSLIGHT

SLIGHTSLIGHT

SLIGHT imbalance to ensure the best possible tracking. When

the scope is on the west side of the mount the counterweight should be

slightly imbalanced to the counterweight bar side. And when the tube is on the

east side of the mount there should be a slight imbalance toward the telescope

side. This is done so that the worm gear is pushing against a slight load. TheThe

TheThe

The

amount of the imbalance is very slight.amount of the imbalance is very slight.

amount of the imbalance is very slight. When taking astrophotographs,

this balance process can be done for the specific area at which the telescope

is pointing to further optimize tracking accuracy.

Balancing theBalancing the

Balancing the

Mount in R.A.Mount in R.A.

Mount in R.A.

Figure 2-15

With the standard accessories attached, the counterweight should be at the far end of

the counterweight bar.

18 • Assembling Your CM-1100

Although the telescope does not track in declination, the telescope should also

be balanced in this axis to prevent any sudden motions when the DEC clutch

knob is loose. To balance the telescope in DEC:

1. Loosen the R.A. clutch knobs and rotate the telescope so that it is on one

side of the mount (i.e., as described in the previous section on “Balancing

the Mount in R.A.”).

2. Tighten the R.A. clutch knobs to hold the telescope in place.

3. Loosen the DEC clutch knobs and rotate the telescope until the tube is

parallel to the ground.

4. Release the tube — GRADUALLYGRADUALLY

GRADUALLYGRADUALLY

GRADUALLY — to see which way it rotates around

the declination axis. DO DO

DO DO

DO NOTNOT

NOTNOT

NOT LET GO OF THE TELESCOPE TUBE LET GO OF THE TELESCOPE TUBE

LET GO OF THE TELESCOPE TUBE LET GO OF THE TELESCOPE TUBE

LET GO OF THE TELESCOPE TUBE

COMPLETELY!COMPLETELY!

COMPLETELY!

5. SlightlySlightly

SlightlySlightly

Slightly loosen the knobs that holds the telescope to the mounting

platform and slide the telescope either forward or backward until it remains

stationary when the DEC clutch is loose. Do NOT let go of the tele-Do NOT let go of the tele-

Do NOT let go of the tele-Do NOT let go of the tele-

Do NOT let go of the tele-

scope tube while the knob on the mounting platform is loose.scope tube while the knob on the mounting platform is loose.

scope tube while the knob on the mounting platform is loose.

6. Tighten the knobs on the telescope mounting platform to hold the tele-

scope in place.

Once the telescope is balanced in declination, slide the dovetail bar safety

clamp down the front of the telescope's slide bar until it touches the mounting

platform and tighten the locking bolt (see Figure 2-16). This not only acts as a

safety in case the mounting platform knobs are loosened, but will also allow

you to put the tube on the mount in the exact same position each time for

perfect balance.

Like R.A. balance, these are general balance instructions and will reduce

undue stress on the mount. When taking astrophotographs, this balance

process should be done for the specific area at which the telescope is pointing.

Balancing the MountBalancing the Mount

Balancing the Mount

in DECin DEC

in DEC

Figure 2-16Figure 2-16

Figure 2-16

With the standard accessories attached, the end of the dovetail bar should be almost

flush with the end of the telescope mounting platform..

Dovetail Slide Bar

Safety Clamp

Assembling Your CM-1100 • 19

Because of the Celestron CM-1100's size and weight, you should ALWAYSALWAYS

ALWAYSALWAYS

ALWAYS

remove the telescope from the mount when moving the telescope. To do so:

1. Take the telescope off of the mount and return it to its shipping box.

2. Remove the counterweight from the counterweight bar.

3. Remove the counterweight bar from the mount.

4. Remove the finderscope from the optical tube.

5. Take the equatorial mount off of the central column.

6. Remove the center leg brace from the tripod.

7. Collapse the tripod legs inward, towards each other.

The telescope is now broken down into enough pieces to be easily transported.

When not in use, your Celestron CM-1100 can be left fully assembled and set

up. However, all lens and eyepiece covers should be put back in place. This

will reduce the amount of dust build-up on all optical surfaces and reduce the

number of times you need to clean the instrument. You may want to return

everything to its original shipping container and store it there. If this is the

case, all optical surfaces should still be covered to prevent dust accumulation.

If you are in the field, and plan on being there for a few days, use a plastic tarp

to cover the telescope and mount.

Transporting YourTransporting Your

Transporting Your

Celestron CM-1100Celestron CM-1100

Celestron CM-1100

Storing Your CelestronStoring Your Celestron

Storing Your Celestron

CM-1100CM-1100

CM-1100

20 • Assembling Your CM-1100

Below is pertinent technical information on your Celestron CM-1100 telescope that you

may find useful.

OPTICAL TUBE:OPTICAL TUBE:

OPTICAL TUBE: CM-1100CM-1100

CM-1100CM-1100

CM-1100 CM-1400CM-1400

CM-1400CM-1400

CM-1400

Optical System: Schmidt-Cassegrain Schmidt-Cassegrain

Aperture: 11" (279mm) 14" (356mm)

Focal Length: 2800mm (110.2") 3910mm (153.9")

F/ratio: f/10 f/11

Highest Useful Power Magnification: 660x 840x

Lowest Useful Power Magnification: 42x 50x

Resolution (arc seconds): 0.41 0.33

Photographic Resolution: 200 lines/mm 182 lines/mm

Light Gathering Power: 1593x 2581x

Limiting Visual Magnitude: 14.7 15.3

Near Focus

with eyepiece: 60' 175'

with camera: 60' 225'

Optical Tube Length: 25" 32"

Weight

Optical Tube: 27.5 lbs. 45 lbs.

DEC AXIS:DEC AXIS:

DEC AXIS:

• All machined stainless steel and aluminum

• 5.625 diameter precision bronze worm gear, 180 tooth. AGMA quality 10.

• .4375 diameter precision 303 stainless steel worm. AGMA quality 10. Dual

bearing supported.

• One inch diameter solid shaft, centerless ground

• Two 2” preloaded Tapper Roller Bearings, pre-loading the shaft.

• Bearing preload is independent of clutch tension.

• Slip Clutch-Variable friction two knob adjustment

• 5.25” laser engraved setting circle, 1 degree increments.

• 182 oz/in Stepper Motor - .50 arc second steps

• Removable stainless steel counterweight shaft

• Dovetail saddle plate – allowing for interchanging of any tube assembly

• Instrument Weight of 60 Lbs

POLAR AXIS:POLAR AXIS:

POLAR AXIS:

• All machined stainless steel and aluminum

• 5.625 diameter precision bronze worm gear, 180 tooth. AGMA quality 10.

• .4375 diameter precision 303 stainless steel worm. AGMA quality 10. Dual

bearing supported.

• One inch diameter solid shaft, centerless ground

• Two 2” preloaded Tapper Roller Bearings, pre-loading the shaft.

• Bearing preload is independent of clutch tension.

• Slip Clutch-Variable friction two knob adjustment

• 5.25” driven laser engraved setting circle, 5 minute increments

(Northern Hemisphere only)

• 182 oz/in Stepper Motor - .50 arc second steps

• Latitude adjustment 20 to 65 degrees with counterweights. Total travel is 13 to

65 degrees.

• Azimuth adjustment, bi-directional +/- 7 degrees

TechnicalTechnical

Technical

SpecificationsSpecifications

Specifications

Assembling Your CM-1100 • 21

TRIPOD:TRIPOD:

TRIPOD:

• All machined aluminum

• Semi-pier Tripod Design

• Fixed hieght Tripod with dual leg support

• Tripod legs are 48.5" long

• Tripod hieght is 49" high (fully extended with column attached)

• Tripod weight approximately 20 pounds

• Weight of equatorial head 31 pounds

CONTROL SYSTEM:CONTROL SYSTEM:

CONTROL SYSTEM:

• Diamond push button pattern

• Hand Control: Reversible R.A. and DEC, Autoguider ready (use an

autoguider and the hand control at the same time)

• Two photo guide rates: .3x, and .5x sidereal

• Three slew rates: 8x, 16x, and 20x (double button hand control, see

chapter on Hand Control use)

• Quartz tracking rates; Sidereal, Solar, Lunar, King

• Periodic Error Correction (PEC)

• Accepts Auto-Guider Systems

• Northern and Southern Hemisphere operation

• Backlash compensation for declination axis.

• 12 Volt DC - 500 MA power use

Note:Note:

Note: All specifications are stated for the Celestron CM telescopes using the

standard accessories. Also, these specifications are approximate and subject

to change without notice.

22 • Telescope Basics

TELESCOPE BASICS

Once your telescope is fully assembled, you are ready for your first look. This

section deals with some of the basics of telescope operation.

The image orientation changes depending on how the eyepiece is inserted into

the telescope. When using the star diagonal, the image is right-side-up, but

reversed from left-to-right (i.e., reverted). If inserting the eyepiece directly into

the visual back (i.e., without the star diagonal), the image is upside-down and

reversed from left-to-right (i.e., inverted). This is normal for the Schmidt-

Cassegrain design and applies to the telescope’s finder as well.

Image Orientation

Figure 3-1

These simplified drawings of the planet Jupiter illustrate the different image orienta-

tions obtained when using various viewing configurations.

Telescope Basics • 23

The Celestron CM-1100 focusing mechanism controls the primary mirror which

is mounted on a ring which slides back and forth on the primary baffle tube.

The focusing knob, which moves the primary mirror, is on the rear cell of the

telescope just right of the star diagonal and eyepiece. Turn the focusing knob

until the image is sharp. If the knob will not turn, it has reached the end of its

travel on the focusing mechanism. Turn the knob in the opposite direction until

the image is sharp. Once an image is in focus, turn the knob clockwise to

focus on a closer object and counterclockwise for a more distant object. A

single turn of the focusing knob moves the primary mirror only slightly. There-

fore, it will take many turns (about 40) to go from close focus (approximately

65 feet) to infinity.

For critical focusing, both visually and photographically, turn the focus knob

counterclockwise until the image is sharp. Turning the focusing knob in this

direction pushes the primary mirror forward, or against the pull of gravity, which

minimizes any mirror shift.

When working with any optical instrument, there are a few things to remember

to ensure you get the best possible image.

•Never look through window glass. Glass found in household windows is

optically imperfect, and as a result, may vary in thickness from one part of a

window to the next. This inconsistency can and will affect the ability to

focus your telescope. In most cases you will not be able to achieve a truly

sharp image. In some cases, you may actually see a double image.

•Never look across or over objects that are producing heat waves. This

includes asphalt parking lots on hot summer days or building rooftops.

•Hazy skies, fog, and mist can also make it difficult to focus when viewing

terrestrially. The amount of detail seen under these conditions is greatly

reduced. Also, when photographing under these conditions, the processed

film may come out a little grainier than normal with lower contrast.

•When using your telescope as a telephoto lens, the split screen or micro-

prism focuser of the 35mm SLR camera may “black out.” This is common

with all long focal length lenses. If this happens, use the ground glass

portion of your focusing screen. To achieve a very sharp focus you may

consider using a focusing magnifier. (These are readily available from your

local camera store.)

•If you wear corrective lenses (specifically glasses), you may want to remove

them when observing with an eyepiece attached to the telescope. When

using a camera, however, you should always wear corrective lenses to

ensure the sharpest possible focus. If you have astigmatism, corrective

lenses must be worn at all times.

Focusing

Figure 3-2

The decal on the end of the

focus knob shows the correct

rotational direction for

focusing the CM-1100.

24 • Telescope Basics

Your Celestron CM-1100 can be used for both terrestrial and astronomical

photography. Your Celestron CM-1100 has a fixed aperture and, as a result, a

fixed f/ratio. To properly expose your subjects photographically you need to

set your shutter speed accordingly. Most 35mm single lens reflex (SLR)

cameras offer through-the-lens metering which lets you know if your picture is

under or overexposed. This is more of a consideration when doing terrestrial

photography, where exposure times are measured in fractions of a second. In

astrophotography, the exposures are much longer, requiring that you use the

“B” setting on your camera. The actual exposure time is determined by how

long you keep the shutter open.

To reduce vibration when tripping the shutter, use a cable release. Releasing

the shutter manually can cause vibration, something that produces blurred

photos. A cable release will keep your hands clear of the camera and tele-

scope, thus reducing the possibility of shaking the telescope. Mechanical

shutter releases can be used, though air type releases are best.

The Celestron CM-1100 comes with an 9x50mm finder which helps in aiming

the main telescope at distant objects that are hard to find in the narrow field of

the telescope. The first number used to describe the finder is the power while

the second number is the diameter of the objective lens in millimeters. This

means the 9x50 finder is 9 power and has a 50mm objective lens. Incidentally,

power is always compared to the unaided human eye. So a 9 power finder

magnifies images nine times more than the human eye.

To make the alignment process a little easier, you should perform this task in

the daytime when it is easier to locate objects in the telescope without the

finder. To align the finder:

1. Choose a conspicuous object that is in excess of one mile away. This will

eliminate any possible parallax effect.

2. Point your telescope at the object you selected and center it in the main

optics of the telescope.

3. Check the finder to see where it is located in the field of view.

4. Adjust the screws on the finder bracket, tightening one while loosening

another, until the cross hairs are centered on the target.

5. Tighten each set screw a quarter of a turn to ensure that they will not

come loose easily.

General Photography

Hints

Aligning the Finder

Figure 3-3

TOP: The image as seen

through the telescope. BOT-

TOM: The image as seen

through the finder.

Telescope Basics • 25

With the telescope fully assembled and all the accessories attached, you are

ready for your first look. Your first look should be done in the daytime when it

is easier to locate the locking clutches. This will help to familiarize you with

your telescope, thus making it easier to use at night.

Daytime Observing

As mentioned in the introduction, your Celestron CM-1100 telescope works

well as a terrestrial spotting scope. When not used to examine objects in the

night sky, it can be used to study objects here on Earth.

WARNING ! NEVER POINT YOUR TELESCOPE AT THE SUN UNLESS YOU HAVE THE

PROPER SOLAR FILTER. PERMANENT AND IRREVERSIBLE EYE DAM-

AGE MAY RESULT AS WELL AS DAMAGE TO YOUR TELESCOPE. ALSO,

NEVER LEAVE YOUR TELESCOPE UNATTENDED DURING A DAYTIME

OBSERVING SESSION, ESPECIALLY WHEN CHILDREN ARE PRESENT.

1. Find a distant object that is fairly bright.

2. Insert a low power eyepiece (one with a large focal length) into the tele-

scope.

3. Adjust the R.A. and DEC clutch knobs if needed and point the telescope in

the direction of the object you selected.

4. Locate the object in your finder.

5. Move the telescope — by hand — until the object is centered in the finder.

6. Look through the main optics and the object will be there (if you aligned

the finder first).

Try using different optional eyepieces to see how the field changes with various

magnifications.

Your First Look

26 • Telescope Basics

Nighttime Observing

Looking at objects in the sky is quite different than looking at objects on Earth.

For one, many objects seen in the daytime are easy to see with the naked eye

and can be located in the telescope by using landmarks. In the night sky

many objects are not visible to the naked eye. To make things easier, you are

better off starting with a bright object like the Moon or one of the planets.

1. Orient the telescope so that the polar axis is pointing as close to true

north as possible. You can use a landmark that you know faces north to

get you in the general direction.

2. Adjust the tripod legs until the mount is level.

3. Adjust the mount until the latitude indicator points to the latitude of the site

from which you are observing.

4. Insert a low power eyepiece (i.e., one with a large focal length) into the

telescope to give you the widest field possible.

5. Turn the clock drive on.

6. Loosen the right ascension and declination clutch knobs and point the

telescope at the desired target. The Moon or one of the brighter planets is

an ideal first target.

7. Locate the object in the finder, center it, and then look through the tele-

scope.

8. Turn the focus knob until the image is sharp.

9. Take your time and study your subject. If observing the Moon, look for

small details in the craters.

That’s all there is to using your Celestron CM-1100. However, don’t limit your

view of an object to a single eyepiece. After a few minutes, try using a different

optional eyepiece, a more powerful one. This gives you an idea of how the field

of view changes. Center your target and focus. Once again, if observing the

Moon you will be looking at a few craters at the same time.

NOTE: If not using the clock drive, the stars will appear to drift out of the field of view.

This is due to the Earth’s rotation. In fact, anything in the sky, day or night,

will drift out unless the telescope has been polar aligned and the clock drive is

running. There is more on this in the section on “Polar Alignment.”

Telescope Basics • 27

You can change the power of your Celestron CM-1100 telescope just by

changing the eyepiece (ocular). To determine the magnification of your

Celestron CM-1100, simply divide the focal length of the telescope by the focal

length of the eyepiece used. In equation format, the formula looks like this:

Focal Length of Telescope (mm)

Magnification = ————————————————

Focal Length of Eyepiece (mm)

Let’s say, for example, that you are using the standard 26mm eyepiece. To

determine the magnification you simply divide the focal length of your Celestron

CM-1100 (2800mm) by the focal length of the eyepiece (26mm). Dividing 2800

by 26 yields a magnification of 108 power.

Although the power is variable, each instrument — under average skies — has

a limit to the highest useful magnification. The general rule is that 60 power

can be used for every inch of aperture. For example, the Celestron CM-1100 is

11" in diameter. Multiplying 11 by 60 gives a maximum useful magnification of

660 power. Although this is the maximum useful magnification, most observ-

ing is done in the range of 20 to 35 power for every inch of aperture which is

220 to 385 times for the CM-1100.

Determining the field of view is important if you want to get an idea of the

angular size of the object you are observing. To calculate the actual field of

view, divide the apparent field of the eyepiece (supplied by the eyepiece

manufacturer) by the magnification. In equation format, the formula looks like

this:

Apparent Field of Eyepiece

True Field = ———————————————

Magnification

As you can see, before determining the field of view, you must figure the

magnification. Using the example in the previous section, we can determine

the field of view using the same 26mm eyepiece. The 26mm Plössl eyepiece

has an apparent field of view of 50°. Divide the 50° by the magnification, which

is 108 power. This yields an actual field of .46°, or about one half of a degree.

To convert degrees to feet at 1,000 yards, which is more useful for terrestrial

observing, simply multiply by 52.5. Continuing with our example, multiply the

angular field .46° by 52.5. This produces a linear field width of 24.2 feet at a

distance of one thousand yards.

The apparent field of each eyepiece that Celestron manufactures is found in the

Celestron Accessory Catalog (#93685).

Calculating

Magnification

Determining Field of

View

28 • Astronomy Basics

ASTRONOMY BASICS

The following section deals with observational astronomy in general. It in-

cludes information on the night sky, polar alignment, and using your telescope

for astronomical observing.

In order to help find objects in the sky, astronomers use a celestial coordinate

system which is similar to our geographical coordinate system here on Earth.

The celestial coordinate system has poles, lines of longitude and latitude, and

an equator. For the most part, these remain fixed against the background

stars.

The celestial equator runs 360 degrees around the Earth and separates the

northern celestial hemisphere from the southern. Like the Earth’s equator, it

bears a reading of zero degrees. On Earth this would be latitude. However, in

the sky this is referred to as declination, or DEC for short. Lines of declination

are named for their angular distance above and below the celestial equator.

The lines are broken down into degrees, minutes and seconds of arc. Declina-

tions south of the equator carry a minus sign (-) in front of the coordinate and

those north of the celestial equator are either blank (i.e., no designation) or

preceded by a plus sign (+).

The celestial equivalent of longitude is called Right Ascension, or R.A. for

short. Like the Earth’s lines of longitude, they run from pole to pole and are

evenly spaced 15 degrees apart. Although the longitude lines are separated by

an angular distance, they are also a measure of time. Each line of longitude is

one hour apart from the next. Since the Earth rotates once every 24 hours,

there are 24 lines total. As a result, the R.A. coordinates are marked off in

units of time. It begins with an arbitrary point in the constellation of Pisces

designated as 0 hours, 0 minutes, 0 seconds. All other points are designated

by how far (i.e., how long) they lag behind this coordinate after it passes

overhead moving towards the west.

Your Celestron CM-1100 telescope comes equipped with setting circles that

translate the celestial coordinates into a precise location for the telescope to

point. The setting circles will not work properly until you have polar aligned the

telescope and aligned the R.A. setting circle.

The Celestial Coordinate

System

Figure 4-1

The celestial sphere seen from the outside showing R.A. and DEC.

Astronomy Basics • 29

The daily motion of the Sun across the sky is familiar to even the most casual

observer. This daily trek is not the Sun moving as early astronomers thought,

but the result of the Earth’s rotation. The Earth’s rotation also causes the

stars to do the same, scribing out a large circle as the Earth completes one

rotation. The size of that circular path a star follows depends on where it is in

the sky. Stars near the celestial equator form the largest circles rising in the

east and setting in the west. Moving toward the north celestial pole, the point

around which the stars in the northern hemisphere appear to rotate, these

circles become smaller. Stars in the mid-celestial latitudes rise in the north-

east and set in the northwest. Stars at high celestial latitudes are always

above the horizon, and are said to be circumpolar because they never rise and

never set. You will never see the stars complete one circle because the

sunlight during the day washes out the starlight. However, part of this circular

motion of stars in this region of the sky can be seen by setting up a camera on

a tripod and opening the shutter for a couple hours. The processed film will

reveal semicircles that revolve around the pole. (This description of stellar

motion also applies to the southern hemisphere except all stars south of the

celestial equator move around the south celestial pole.)

Motion of the Stars

Figure 4-2

All stars appear to rotate around the celestial poles. However, the appearance of this

motion varies depending on where you are looking in the sky. Near the north celestial

pole the stars scribe out recognizable circles centered on the pole (1). Stars near the

celestial equator also follow circular paths around the pole. But, the complete path is

interrupted by the horizon. These appear to rise in the east and set in the west (2).

Looking toward the opposite pole, stars curve or arc in the opposite direction scribing a

circle around the opposite pole (3).

30 • Astronomy Basics

In order for the telescope to track the stars, you must meet two criteria. First,

you need a drive motor that moves at the same rate as the stars. The

Celestron CM-1100 comes standard with a built-in drive motor designed

specifically for this purpose. The second thing you need is to set the

telescope’s axis of rotation so that it tracks in the right direction. Since the

motion of the stars across the sky is caused by the Earth’s rotation about its

axis, the telescope’s axis must be made parallel to the Earth’s.

Polar alignment is the process by which the telescope’s axis of rotation (called

the polar axis) is aligned (made parallel) with the Earth’s axis of rotation. Once

aligned, a telescope with a clock drive will track the stars as they move across

the sky. The result is that objects observed through the telescope appear

stationary (i.e., they will not drift out of the field of view). If not using the clock

drive, all objects in the sky (day or night) will slowly drift out of the field. This

motion is caused by the Earth’s rotation. Even if you are not using the clock

drive, polar alignment is still desirable since it will reduce the number of

corrections needed to follow an object and limit all corrections to one axis

(R.A.). There are several methods of polar alignment, all of which work on a

similar principle, but performed somewhat differently. Each method is consid-

ered separately, beginning with the easier methods and working to the more

difficult.

Although there are several methods mentioned here, you will never use all of

them during one particular observing session. Instead, you may use only one

if it is a casual observing session. Or, you may use two methods, one for

rough alignment followed by a more accurate method if you plan on doing

astrophotography.

Definition: The polar axis is the axis around which the telescope rotates when moved in

right ascension. This axis points the same direction even when the telescope

moves in right ascension.

Figure 4-3

Polar Alignment

Astronomy Basics • 31

In each hemisphere, there is a point in the sky around which all the other stars

appear to rotate. These points are called the celestial poles and are named for

the hemisphere in which they reside. For example, in the northern hemisphere

all stars move around the north celestial pole. When the telescope’s polar axis

is pointed at the celestial pole, it is parallel to the Earth’s rotational axis.

Many of the methods of polar alignment require that you know how to find the

celestial pole by identifying stars in the area. For those in the northern

hemisphere, finding the celestial pole is not too difficult. Fortunately, we have

a naked eye star less than a degree away. This star, Polaris, is the end star

in the handle of the Little Dipper. Since the Little Dipper (technically called

Ursa Minor) is not one of the brightest constellations in the sky, it may be

difficult to locate from urban areas. If this is the case, use the two end stars in

the bowl of the Big Dipper (the pointer stars). Draw an imaginary line through

them toward the Little Dipper. They point to Polaris. The position of the Big

Dipper changes during the year and throughout the course of the night. When

the Big Dipper is low in the sky (i.e., near the horizon), it may be difficult to

locate.

Observers in the southern hemisphere are not as fortunate as those in the

northern hemisphere. The stars around the south celestial pole are not nearly

as bright as those around the north. The closest star that is relatively bright is

Sigma Octantis. This star is just within naked eye limit (magnitude 5.5) and

lies about 59 arc minutes from the pole. For more information about stars

around the south celestial pole, please consult a star atlas.

Definition: The north celestial pole is the point in the northern hemisphere around which

all stars appear to rotate. The counterpart in the southern hemisphere is

referred to as the south celestial pole.

Finding the Pole

Figure 4-4

The position of the Big

Dipper changes through-

out the year and through-

out the night.

Figure 4-5

The two stars in the front of the bowl of the Big Dipper point to Polaris which is less

than one degree from the true (north) celestial pole. Cassiopeia, the “W” shaped

constellation is on the opposite side of the pole from the Big Dipper. The North

Celestial Pole (N.C.P.) is marked by the “+” sign.

Spring

Winter

Summer

Fall

32 • Astronomy Basics

Latitude Scales

The easiest way to polar align a telescope is with a latitude scale. Unlike

other methods that require you to find the celestial pole by identifying certain

stars near it, this method works off of a known constant to determine how high

the polar axis should be pointed. The Celestron CM-1100 mount can be

adjusted from 13 to 65 degrees (see figure 4-6).

The constant, mentioned above, is a relationship between your latitude and the

angular distance the celestial pole is above the northern (or southern) horizon;

The angular distance from the northern horizon to the north celestial pole is

always equal to your latitude. To illustrate this, imagine that you are standing

on the north pole, latitude +90°. The north celestial pole, which has a declina-

tion of +90°, would be directly overhead (i.e., 90 above the horizon). Now, let’s

say that you move one degree south — your latitude is now +89° and the

celestial pole is no longer directly overhead. It has moved one degree closer

toward the northern horizon. This means the pole is now 89° above the

northern horizon. If you move one degree further south, the same thing

happens again. You would have to travel 70 miles north or south to change

your latitude by one degree. As you can see from this example, the distance

from the northern horizon to the celestial pole is always equal to your latitude.

If you are observing from Los Angeles, which has a latitude of 34°, then the

celestial pole is 34° above the northern horizon. All a latitude scale does then

is to point the polar axis of the telescope at the right elevation above the

northern (or southern) horizon. To align your telescope:

1. Make sure the polar axis of the mount is pointing due north. Use a

landmark that you know faces north.

2. Level the tripod. There is a bubble level built into the mount for this

purpose.

NOTE: Leveling the tripod is only necessary if using this method of polar

alignment. Perfect polar alignment is still possible using other

methods described later in this manual without leveling the tripod.

3. Adjust the mount in altitude until the latitude indicator points to your

latitude. Moving the mount affects the angle the polar axis is pointing. For

specific information on adjusting the equatorial mount, please see the

section “Adjusting the Mount.”

This method can be done in daylight, thus eliminating the need to fumble

around in the dark. Although this method does NOT put you directly on the

pole, it will limit the number of corrections you will make when tracking an

object. It will also be accurate enough for short exposure prime focus plan-

etary photography (a couple of seconds) and short exposure piggyback

astrophotography (a couple of minutes).

Figure 4-6

The altitude scale allows for

settings between 13 and 65

degrees.

Latitude Scale

Altitude Adjustment Knob

Astronomy Basics • 33

Pointing at Polaris

This method utilizes Polaris as a guidepost to the celestial pole. Since Polaris

is less than a degree from the celestial pole, you can simply point the polar

axis of your telescope at Polaris. Although this is by no means perfect

alignment, it does get you within one degree. Unlike the previous method, this

must be done in the dark when Polaris is visible.

1. Set the telescope up so that the polar axis is pointing north.

2. Loosen the DEC clutch knob and move the telescope so that the tube is

parallel to the polar axis. When this is done, the declination setting circle

will read +90°. If the declination setting circle is not aligned, move the

telescope so that the tube is parallel to the polar axis.

3. Adjust the mount in altitude and/or azimuth until Polaris is in the field of

view of the finder.

4. Center Polaris in the field of the telescope using the fine adjustment

controls on the mount.

Remember, while Polar aligning, do NOT move the telescope in

R.A. or DEC. You do not want to move the telescope itself, but the

polar axis. The telescope is used simply to see where the polar

axis is pointing.

Like the previous method, this gets you close to the pole but not directly on it.

The following methods help improve your accuracy for more serious observa-

tions and photography.

Figure 4-7

One might think that pointing at the pole produces a parallax effect, thus skewing the

telescope’s axis of rotation with that of the Earth’s. Polaris, however, is over 50 light

years away, thus making any parallax effect negligible. (One light year is 6.4 trillion

miles. To find the distance to Polaris in miles, multiply 6.4 trillion by 50!)

34 • Astronomy Basics

The Polar Axis Finder

The Polar Axis Finder is designed to minimize polar alignment time while

maintaining maximum accuracy. The installation of this accessory is de-

scribed in the section on “Installing the Polar Axis Finder.”

Here’s how to use it:

1. Wait until it is dark enough to see Polaris with the unaided eye.

2. Place Polaris in the center of the crosshairs of the polar axis finder by

adjusting the mounts latitude and azimuth controls (see figure 2-14 on

page 16).

3. Rotate the polar scope until the small circle (located along the inner ring of

the reticle) is positioned towards the celestial pole (see Figures 4-8 and 4-

9). You may need to loosen the nylon tension screws on the polar finder

bracket.

Remember that the north celestial pole is located by moving away from Polaris

in the direction of the last star (Alkaid) in the handle of the Big Dipper .

4. Adjust the mount in altitude and azimuth until Polaris is in the small circle

indicating the celestial pole.

When finished, the mount is accurately polar aligned.

Figure 4-8

In this example the North Celestial Pole (NCP) is located approximately in the "11 O'clock" position relative to Polaris

(Figure 4-9). Therefore, the polar finder reticle must be rotated to match the view as seen through the polar axis finder

(Figure 4-8). Now, simply adjust the telescope's latitude and azimuth controls until Polaris is positioned in the small

circle.

Figure 4-9

Put Polaris Here

Astronomy Basics • 35

Declination Drift

This method of polar alignment allows you to get the most accurate alignment

on the celestial pole and is required if you want to do long exposure deep-sky

astrophotography through the telescope. The declination drift method requires

that you monitor the drift of selected guide stars. The drift of each guide star

tells you how far away the polar axis is pointing from the true celestial pole and

in what direction. Although declination drift is quite simple and straight-

forward, it requires a great deal of time and patience to complete when first

attempted. The declination drift method should be done after any one of the

previously mentioned methods has been completed.

To perform the declination drift method you need to choose two bright stars.

One should be near the eastern horizon and one due south near the meridian.

Both stars should be near the celestial equator (i.e., 0° declination). You will

monitor the drift of each star one at a time and in declination only. While

monitoring a star on the meridian, any misalignment in the east-west direction

will be revealed. While monitoring a star near the east/west horizon, any

misalignment in the north-south direction will be revealed. As for hardware,

you will need an illuminated reticle ocular to help you recognize any drift. For

very close alignment, a Barlow lens is also recommended since it increases

the magnification and reveals any drift faster.

When looking due south with the scope on the side of the mount, insert the

diagonal so it points straight up. Insert a cross hair ocular and align the cross

hairs to be parallel to declination and right ascension motion. Use ± 16x guide

setting to check parallelism.

First choose your star near where the celestial equator and the meridian meet.

The star should be approximately ±1/2 hour of the meridian and ±5 degrees of

the celestial equator. Center the star in the field of your telescope and monitor

the drift in declination.

•If the star drifts south, the polar axis is too far east.

•If the star drifts north, the polar axis is too far west.

Make the appropriate adjustments to the polar axis to eliminate any drift.

Once you have managed to eliminate all drift, move to the star near the eastern

horizon. The star should be 20 degrees above the horizon and ± 5 degrees of

the celestial equator.

•If the star drifts south, the polar axis is too low.

•If the star drifts north, the polar axis is too high.

Once again, make the appropriate adjustments to the polar axis to eliminate

any drift. Unfortunately, the latter adjustments interact with the prior adjust-

ments ever so slightly. So, repeat the process again to improve the accuracy

checking both axes for minimal drift. Once the drift has been eliminated, the

telescope is very accurately aligned. You will now be able to do prime focus

deep-sky astrophotography for long periods.

NOTE: If the eastern horizon is blocked, you may choose a star near the western

horizon. However, you will have to reverse the polar high/low error directions. If

using this method in the southern hemisphere, the procedure is the same as

described above. However, the direction of drift is reversed.

36 • Astronomy Basics

Before you can use the setting circles to find objects in the sky, you need to

align both the R.A. and DEC setting circles. In order to align the setting circle,

you need to know the names of a few of the brightest stars in the sky. If you

don’t, they can be learned by using the Celestron Sky Maps (#93722) or

consulting a current astronomy magazine. To align the R.A. setting circle:

1. Locate a bright star near the celestial equator. The farther you are from

the celestial pole, the better your reading of the R.A. setting circle. The

star you choose to align the setting circle with should be a bright one

whose coordinates are known and easy to look up. (For a list of bright

stars to align the R.A. setting circle, see the list at the back of this

manual.)

2. Center the star in the finder.

3. Center the star in the field of the telescope.

4. Start the clock drive so that the mount tracks the star.

5. Look up the coordinates of the star. You can consult a star catalog or use

the list at the end of this manual.

6. Rotate the circle until the proper coordinates line up with the R.A. indica-

tor. The R.A. setting circle should rotate freely. The R.A. setting circle

has a marker every four minutes with each hour labeled (see figure 4-10).

The R.A. setting circle is now aligned and ready to use. The R.A. setting

circle is clutched to the R.A. gear rotation. As long as the R.A. drive is

operating, the circle does not need to be reset once indexed to the correct

coordinate (i.e., once aligned). If the drive is ever turned off, then the R.A.

setting circle must be reset once activated. While the R.A. setting circle

tracks with the drive motor, it does not move when slewing the telescope.

Aligning the R.A.

Setting Circle

Figure 4-10

Setting the DEC

Circle The declination setting circle is fixed in place and cannot be moved be hand.

Once the mount is polar aligned with the DEC circle reading 90°, simply move

the telescope in declination until the desired coordinance are reached.

Using the Drive • 37

Figure 5-1

The CI-700 electronic console.

Powering Up the

Drive

USING THE DRIVE

The drive system uses a 5.625 diameter bronze gear with 180 teeth for incred-

ibly accurate tracking. One of the most unique features of the drive is the

Periodic Error Correction (PEC) function. This feature allows the drive system

to “learn” the characteristics of the worm gear, and as a result, improve the

tracking accuracy even more. This typically reduces the periodic error to 30

percent or less of the original error. The amount of improvement varies depend-

ing on guiding skill, atmospheric stability, the characteristics of the worm gear,

and the accuracy of polar alignment.

Following is a brief discussion of each feature.

In order to activate the drive, you must first plug it into an external power

source. To supply power to your Celestron CM-1100, plug your Car Battery

Adapter or optional AC Adapter into the outlet on the electronic console

labeled “12 VDC.” Then, plug the other end of the adapter into the appropriate

power source (i.e., either AC or DC depending on the adapter used).

Next, plug the R.A. and DEC cables into the electronic box. The DEC cable

has a modular phone jack connector on each end. Plug one end into the DEC

Motor receptacle on the electronics console and the other end into the declina-

tion motor. The R.A. cable has a modular phone jack connector at one end

and a 5-pin connector at the other end. Attach the 5-pin connector over the 5

pins at the top of the electronics module (labled R.A. Motor), and then plug the

phone jack connector into the R.A. motor.

Once plugged into the proper power source, activate the drive by placing the

ON/OFF switch in the “ON” position. Once activated, the drive begins tracking

at sidereal rate, the default tracking rate. The LED next to the sidereal rate

icon will illuminate.

38 • Using the Drive

This function allows you to select the speed at which the motor moves when

corrections are made via the hand controller. Once the drive is activated, the

default setting is .3 times sidereal rate. Press the Speed button to change the

guiding rate. The selections are .3x, .5x, 8x, and 16x sidereal rate.

For guiding, use either the .3x or .5x setting. These two rates allow optimal

use with autoguiders. The faster settings — 8x and 16x — are perfect for

positioning objects within the field of view.

The telescope can also move at 20x speed WITHOUT changing any of the

guide settings. To control the telecope at 20x speed, press the button that

corresponds to the direction you want to move the telescope. While holding

the button down, press the opposite directional button. For example, if you

want to move the telescope west, hold the west button down and then press

the east button. Conversely, if you want to move the telescope east, hold the

east button down and then press the west button. This “fast-set” function also

works in declination. It should be noted that the R.A. setting circle does not

remain calibrated when using any of the slewing rates.

NOTE: If the 20x speed is not functioning (but all other speeds do), it is

probably due to low voltage from your power source.

The drive has four basic rates: sidereal, solar, lunar and King (which is a

modified sidereal rate that takes into account atmospheric refraction). While

solar and lunar rates are obvious, sidereal and King rates require a little more

explaining. Sidereal rate is based on a single rotation of the Earth which takes

1,436.5 minutes. An astronomer by the name of King discovered that atmo-

spheric refraction affects the apparent motion of objects across the sky. The

King rate takes into account this refraction caused by the Earth’s atmosphere

and is recommended for deep-sky astrophotography. For deep-sky observing,

either King or sidereal rate is fine.

Each of the tracking rates is represented by an icon. Sidereal rate is repre-

sented by a star ( ), solar rate by a sun ( ), lunar rate by a crescent moon

( ) and King rate by a crown ( ) . Next to each icon is an LED to indicate

which rate has been selected. Once the power has been turned on, the drive

tracks at sidereal rate, the default tracking rate. To change the tracking rate,

press the “TRACK RATE” button. Pressing the button once changes the drive

rate once. The rates are selected sequentially from bottom-to-top as listed

above.

Note that the PEC function does NOT have to be activated for the drive to work.

However, once PEC is activated, the drive rate is locked on the one selected.

You can not change rates until PEC is turned off.

Guide Speed

Figure 5-3

Tracking Rate Selection

Figure 5-2

Using the Drive • 39

RATE

The BC (Backlash Correction) function allows you to eliminate the backlash in

the DEC motor when changing directions (i.e., from north to south or vice

versa). Here’s how it works. Each time you change the direction of the

telescope in declination, the motor speeds up momentarily to take up any

slack. The Tracking Rate and Guide Speed displays are used to regulate the

"aggressiveness" of the backlash compensation. The best setting is deter-

mined by looking through the eyepiece while changing the direction of the DEC

motor and then moving through the BC button settings until the backlash has

been eliminated.

To activate this function, press the BC button. Once activated, the .3x guide

speed and sidereal tracking LED will flash rapidly. Use the east and west (left

and right) buttons on the hand control to change the backlash compensation

speed. Press the right hand control button and the next guide speed light (.5x)

will illuminate. When the hand control button is pressed four times, the next

tracking rate light ( ) will illuminate. Continue pressing the hand control

buttons until the desired compensation speed is reached or until you reach the

highest setting (16x and ). Once the desired level is set, press the BC

button again to activate backlash correction. The BC must be reset each time

you power up the drive.

Periodic Error Correction, or PEC for short, is a system that improves the

tracking accuracy of the drive. PEC is designed to improve photographic

quality by reducing the amplitude of the worm errors. Using the PEC function

is a two-step process. First, you must guide for at least eight minutes —

keeping the guide star centered on the cross hairs of your optional guiding

eyepiece — during which time the system records the corrections you make.

(It takes the worm gear eight minutes to make one complete revolution, hence

the need to guide for eight minutes). The second step is to play back the

corrections you made during the recording phase. The microcomputer inside

the electronic console does this automatically after one revolution of the worm

gear.

Periodic error is a slight oscillation in right ascension caused by imperfections

in all drive gears. The cycle of the periodic error is equal to the rotation of the

[worm] gear, in this case eight minutes. All telescope drives with gears have

some periodic error. The periodic error of your Celestron CM-1100 is very

slight to begin with.

Keep in mind, this feature is for advanced astrophotographers and requires

careful guiding. Here’s how to use the PEC function most effectively.

1. Find a bright star relatively close to the object you want to photograph.

2. Insert a high power eyepiece with illuminated cross hairs into your tele-

scope. Orient the guiding eyepiece cross hairs so that one is parallel to

the declination axis while the other is parallel to the R.A. axis.

3. Center the guide star on the illuminated cross hairs, focus the telescope,

and study the periodic movement.

4. Take a few minutes to practice guiding. This will help you familiarize

yourself with the periodic error of the drive and the operation of the hand

control box.

Periodic Error Correc-

tion

(PEC)

BC — Backlash

Correction

Figure 5-4—The guide rate and

tracking rate lights are used to

indicate the amount of

backlash correction.

Definition:

40 • Using the Drive

12 V DC

5. Press the “PEC” button once to activate the mode. The LED will flash

once a second for 5 seconds indicating you have five seconds to get back

to the eyepiece and begin guiding before it begins recording. The .3x

guiding rate is best for this function.

NOTE: The star should stay centered on the cross hairs for a few seconds

without using the hand controller before activating the PEC func-

tion.

6. Guide for eight minutes. Try not to overshoot corrections in right ascen-

sion. Ignore drift in declination. During the record phase, the LED flashes

a little faster.

After eight minutes, the system begins to play back the corrections made

during the first eight minutes. When playing back, the LED stays on without

blinking.

If you press the PEC button while it is in playback mode, you will lose the

previously recorded information. Also, the fast slew functions are locked while

the PEC function is activated. This eliminates the possibility of shifting the

focus or moving the telescope suddenly during an exposure.

The fast-set function is locked while the PEC function is activated. This

eliminates the possibility of moving the telescope suddenly during an expo-

sure.

Once you have used the PEC function for awhile you may mistake its opera-

tion for the way the drive normally operates. The best way to see how well the

PEC function works is to turn it off. PEC results improve with practice and

patience.

This outlet accepts the hand controller needed for guiding and moving the

telescope. This outlet uses a modular phone-type jack. Push the connector

on the cable into the outlet until the plastic tab clicks. To remove the cable,

squeeze the plastic tab and pull away from the outlet.

This outlet is used to supply power to the telescope. Your Celestron CM-1100

comes standard with a Car Battery Adapter. To install the adapter, plug the

connector into the electronic console first, then the power source (automobile

cigarette lighter receptacle).

HC/CCD

NOTE:

Using the Drive • 41

The Hand Controller

When using your Celestron CM-1100 in the southern hemisphere, there is a

need to reverse the motors. Changing from northern hemisphere to southern

hemisphere requires changing the polarity of the drive motor by changing the

settings of the dip switches on the electronics board. To do this:

1. Remove the cover of the electronic console by removing the four screws

(one in each corner).

2. Remove the two screws (one directly above the DEC motor jack and the

other next to the On/Off indicator light) that attach the cover to the elec-

tronics board where the dip switches are located.

3. Locate the dip switches on the electronics board as shown on figure 5-5.

4. For operation in the southern hemisphere, set switch 4 to the OFF or down

position (see Figure 5-6).

The direction of the drive motor is now reversed and will work in the southern

hemisphere. If going from the southern hemisphere to the northern hemi-

sphere, simply change the switch back to the ON or up position.

The hand controller allows you to move the telescope in R.A. and DEC using

the corresponding motors. This includes fine corrections for guided astropho-

tography and minor adjustments for centering objects in the field of view.

The buttons on the hand controller are intentionally labeled in a rather vague

manner. This is due to the fact that the direction of motion of the mount varies

depending on how the telescope is oriented. Furthermore, these buttons are

user definable to eliminate confusion when guiding. (For more information, see

the section on “R.A./DEC Reverse.”)

Once again, to move the telescope at the 20x speed WITHOUT changing the

guide setting, press the button that corresponds to the direction you want to

move the telescope. While holding the button down, press the opposite

directional button. For example, if you want to move the telescope west, hold

the west button down and then press the east button. Conversely, if you want

to move the telescope east, hold the east button down then press the west

button. The fast-set function also works in declination.

Northern/Southern

Hemisphere Operation

Figure 5-5 Figure 5-6

42 • Using the Drive

R.A./DEC Reverse

As mentioned previously, the direction a particular button moves the mount

varies depending on the telescope’s orientation (i.e., whether it’s on the east or

west side of the mount). This can create confusion when guiding if you change

the telescope’s orientation during a given photographic session. To compen-

sate for this, the direction of the R.A. and DEC buttons are changeable. To

reverse the direction of either the R.A. and/or DEC buttons, change the switch

setting of the appropriate axis (see Figure 5-7).

Autoguiding

On the top side of the hand controller you will find a phone jack outlet desig-

nated for use with an autoguider. Most CCD autoguiders will require a cable

that attaches the autoguider to your telescope's drive controller via the hand

controller outlet, rendering the hand controller inoperable. By plugging the

autoguider cable directly into the hand controller, you have the ability to

override the autoguider and make manual corrections with the hand controller

buttons.

Figure 5-7

Reverse switches

Guiding Buttons

Celestial Observing • 43

CELESTIAL OBSERVING

With your telescope set up, you are ready to use it for observing. This section

covers visual observing of both solar system and deep-sky objects.

In the night sky, the Moon is a prime target for your first look because it is

extremely bright and easy to find. Often, it is a temptation to look at the Moon

when it is full. At this time, the face we see is fully illuminated and its light can

be overpowering. In addition, little or no contrast can be seen during this

phase.

One of the best times to observe the Moon is during its partial phases (around

the time of first or third quarter). Long shadows reveal a great amount of detail

on the lunar surface. At low power you will be able to see most of the lunar

disk at one time. The optional Reducer/Corrector lens allows for breathtaking

views of the entire lunar disk when used with a low power eyepiece. Change to

higher power (magnification) to focus in on a smaller area. Keep in mind that if

you are not using the clock drive, the rotation of the Earth will cause the Moon

to drift out of your field of view. You will have to manually adjust the telescope

to keep the Moon centered. This effect is more noticeable at higher power. If

you are using the clock drive and have polar aligned, the Moon will remain

centered if using the lunar tracking rate. Consult your local newspaper or a

current astronomy magazine to find out when the Moon will be visible.

LUNAR OBSERVING HINTS

•To ensure accurate tracking, be sure to select the lunar tracking rate.

•Try using eyepiece filters to increase contrast and bring out more detail on

the lunar surface.

Other easy targets in the night sky include the five naked eye planets. You

can see Venus go through its lunar-like phases. Mars can reveal a host of

surface detail and one, if not both, of its polar caps. You will be able to see

the cloud belts of Jupiter and the great Red Spot (if it is visible at the time you

are observing). In addition, you will also be able to see the moons of Jupiter as

they orbit this gas giant. Saturn, with its beautiful rings, is easily visible at

moderate power. All you need to know is where to look. Most astronomy

publications tell where the planets can be found in the sky each month.

King or sidereal rates work best for tracking the planets.

Observing the Moon

Observing the Planets

Figure 6-1

This scanned drawing of

Jupiter provides a good

representation of what you

can expect to see with

moderate magnification

during good seeing conditions.

44 • Celestial Observing

Although overlooked by many amateur astronomers, solar observation is both

rewarding and fun. However, because the Sun is so bright, special precautions

must be taken when observing our star so as not to damage your eyes or your

telescope.

WARNING: Never project an image of the Sun through the telescope. Because of

the folded optical design, tremendous heat buildup will result inside the

optical tube. This can damage the telescope and/or any accessories

attached to the telescope.

For safe solar viewing, use a solar filter. These filters reduce the intensity of

the Sun’s light, making it safe to view. With these filters you can see sun-

spots as they move across the solar disk and faculae, which are bright

patches seen near the Sun’s edge. Be sure to cover the lens of the finder

or completely remove the finder when observing the Sun. This will

ensure that the finder itself is not damaged and that no one looks

through it inadvertently.

SOLAR OBSERVING HINTS

•The best time for observing the Sun is in the early morning or late after-

noon when the air is cooler.

•To locate the Sun without a finder, watch the shadow of the optical tele-

scope tube until it forms a circular shadow.

•To ensure accurate tracking, be sure to select the solar tracking rate.

Observing the Sun

Celestial Observing • 45

Deep-sky objects are simply those objects outside the boundaries of our solar

system. They include star clusters, planetary nebulae, diffuse nebulae, double

stars, and other galaxies outside our own Milky Way. The Celestron Sky

Maps (#93722) can help you locate the brightest deep-sky objects. You can

use your setting circles or “star hop” to an object from an area with which you

are familiar.

Most deep-sky objects have a large angular size. Therefore, low-to-moderate

power is all you need to see them. Visually, they are too faint to reveal any

color seen in long exposure photographs. Instead, they have a black and white

appearance. And, because of their low surface brightness, they should be

observed from a dark sky location. Light pollution around large urban areas

washes out most nebulae making them difficult, if not impossible, to observe.

Light Pollution Reduction filters help reduce the background sky increasing

contrast.

Using Your Setting Circles

Once the setting circles are aligned you can use them to find any object with

known coordinates.

1. Select an object to observe. Use a seasonal star chart or planisphere to

make sure the object you chose is above the horizon. As you become

more familiar with the night sky, this will no longer be necessary.

2. Look up the coordinates in an atlas or reference book.

3. Move the telescope in declination until the indicator is pointing at the

correct declination coordinate.

4. Move the telescope in R.A. until the indicator points to the correct coordi-

nate (do NOT move the R.A. circle). The telescope will track in R.A. as

long as the clock drive is operating.

5. Look through the finder to see if you have located the object.

6. Center the object in the finder.

7. Look in the main optics using a low power eyepiece; the object should be

there.

8. Repeat the process for each object observed throughout the observing

session.

You may not be able to see fainter objects in the finder. When this happens,

gradually sweep the telescope around until the object is visible.

The declination setting circle is scaled in degrees while the R.A. setting circle

is incremented in minutes with a marker every five minutes (see figure 6-2). As

a result, the setting circles will get you close to your target, but not directly on

it. Also, the accuracy of your polar alignment will also affect how accurately

your setting circles read. It should be noted that the R.A. setting circle does

not remain calibrated when using any of the slewing rates.

At the end of this manual there is a list of deep-sky objects well within reach of

your Celestron CM-1100 telescope.

Observing Deep-Sky

Objects

Figure 6-2

The R.A. setting circle (top) and

the DEC circle (bottom).

50 60 70 80

46 • Celestial Observing

Star Hopping

Another way to find deep-sky objects is by star hopping. Star hopping is done

by using bright stars to “guide” you to an object. Here are the directions for

two popular objects.

The Andromeda Galaxy, M31, is an easy target. To find M31:

1. Locate the constellation of Pegasus, a large square visible in the fall and

winter months.

2. Start at the star in the northeast corner. The star is Alpha (α)

Andromedae.

3. Move northeast approximately 7°. There you will find two stars of equal

brightness — Delta (δ) and Pi (π) Andromedae — about 3° apart.

4. Continue in the same direction another 8°. There you will find two stars —

Beta (β) and Mu (µ) Andromedae — about 3° apart.

5. Move 3° northwest — the same distance between the two stars — to the

Andromeda galaxy. It is easily visible in the finder.

Figure 6-3

Star hopping to the Andromeda Galaxy is a snap to find since all the stars needed to do

so are visible to the naked eye. Note that the scale for this star chart is different from

the one on the following page which shows the constellation Lyra.

Celestial Observing • 47

Star hopping may take some getting used to since you can see more stars

through the finder than you can see with the naked eye. And, some objects

are not visible in the finder. One such object is M57, the famed Ring Nebula.

Here’s how to find it:

1. Find the constellation of Lyra, a small parallelogram visible in the summer

and fall months. Lyra is easy to pick out because it contains the bright

star Vega.

2. Start at the star Vega — Alpha (α) Lyrae — and move a few degrees

southeast to find the parallelogram. The four stars that make up this

geometric shape are all similar in brightness making them easy to see.

3. Locate the two southernmost stars that make up the parallelogram —

Beta (β) and Gamma (γ) Lyrae.

4. Point the finder half way between these two stars.

5. Move about 1/2° toward Beta (β) Lyrae, but remaining on a line that

connects the two stars.

6. Look through the telescope and the Ring Nebula should be in the tele-

scope. Its angular size is quite small and, therefore, not visible in the

finder.

Because the Ring Nebula is rather faint, you may need to use averted vision to

see it. Averted vision is the act of looking slightly away from the object you are

observing. So, if you are observing the Ring Nebula, center it in the field of

view and then look off toward the side. In this manner, light from the object is

falling on the black and white sensitive rods as opposed to the color sensitive

cones. These two examples should give you an idea of how to star hop to

deep-sky objects. To use this method on other objects, consult any of the star

atlases and star hop to the object of your choice using naked eye stars.

Figure 6-4

Although the Ring Nebula lies

between two naked eye stars, it

may take a little time to locate

since it is not visible in the

finder. Note that the scale for

this star chart is different from

the one on the previous page

which shows several constella-

tions including Pegasus,

Triangulum, and Andromeda.

48 • Celestial Observing

Viewing conditions affect what you can see through your CM-1100 telescope

during an observing session. Conditions include transparency, sky illumina-

tion, and seeing. Understanding viewing conditions and the effect they have on

observing will help you get the most out of your CM-1100 telescope.

Transparency

Transparency is the clarity of the atmosphere and is affected by clouds,

moisture, and other airborne particles. Thick cumulus clouds are completely

opaque while cirrus clouds can be thin, allowing the light from the brightest

stars through. Hazy skies absorb more light than clear skies making fainter

objects harder to see and reducing contrast on brighter objects. Aerosols

ejected into the upper atmosphere from volcanic eruptions also affect transpar-

ency. Ideal conditions are when the night sky is inky black.

Sky Illumination

General sky brightening caused by the Moon, aurorae, natural airglow, and

light pollution greatly affect transparency. While not a problem for the brighter

stars and planets, bright skies reduce the contrast of extended nebulae

making them difficult, if not impossible, to see. To maximize your observing,

limit deep-sky viewing to moonless nights far from the light polluted skies found

around major urban areas. You can, on the other hand, observe planets and

stars from light polluted areas or when the Moon is out.

Seeing Conditions

Seeing conditions refer to the stability of the atmosphere and directly effects

the clarity of star images and the amount of fine detail seen in extended

objects. The air in our atmosphere acts as a lens which bends and distorts

incoming light rays. The amount of bending depends on air density. Varying

temperature layers have different densities and therefore bend light differently.

Light rays from the same object arrive slightly displaced creating an imperfect

or smeared image. These atmospheric disturbances vary from time-to-time

and place-to-place. The size of the air parcels compared to your aperture

determines the “seeing” quality. Under good seeing conditions, fine detail is

visible on the brighter planets like Jupiter and Mars, and stars are pinpoint

images. Under poor seeing conditions, images are blurred and stars appear as

blobs. Seeing conditions are rated on a five-point scale where one is the worst

and five is the best (see figure 6-5). Seeing conditions can be classified in one

of three categories.

Type 1 seeing conditions are characterized by rapid changes in the image

seen through the telescope. Extended objects, like the Moon, appear to

shimmer while point sources (i.e., stars) appear double. Type 1 seeing is

caused by currents within or very close to the telescope tube. These currents

could be caused by a telescope that has not reached thermal equilibrium with

the outdoor surroundings, heat waves from people standing near the telescope,

or heated dew caps. To avoid the problems associated with Type 1 seeing,

allow your telescope at least 45 minutes to reach thermal equilibrium. Once

adjusted to the outdoor temperature, don’t touch the telescope tube with your

hands. If observing with others, make sure no one stands in front of or directly

below the telescope tube.

Viewing Conditions

Celestial Observing • 49

Type 2 seeing conditions do move as quickly as Type 1, though the image is

quite blurry. Fine detail is lost and the contrast is low for extended objects.

Stars are spread out and not sharp. The source of Type 2 seeing is the lower

atmosphere, most likely heat waves from the ground or buildings. To avoid the

problems associated with Type 2 seeing, select a good observing site. Specifi-

cally, avoid sites that overlook asphalt parking lots or ploughed fields. Stay

away from valleys and shorelines. Look for broad hilltops or open grassy

fields. Stable thermal conditions found near lakes and atmospheric inversions

also tend to produce good seeing. If you can’t get a better location, wait until

the early morning hours when the surroundings are uniformly cool and the

seeing is generally better.

Type 3 seeing conditions are characterized by fast ripples, but sharp images.

In extended objects fine detail is visible, but the image shifts around the field.

Stars are crisp points, but they shift small distances rapidly around the field.

The cause of Type 3 seeing is turbulence in the upper atmosphere which

means the observer has less control over it. However, the effects of Type 3

seeing are generally less pronounced that the other two types. You can never

really avoid Type 3 seeing. Your best bet is to wait until moments of steadi-

ness. If the seeing is extremely bad, pack up and wait for a better night.

The conditions described here apply to both visual and photographic observa-

tions.

Figure 6-5

Seeing conditions directly affect image quality. These drawings represent a point

source (i.e., star) under bad seeing conditions (left) to excellent conditions (right).

Most often, seeing conditions produce images that lie some where between these two

extremes.

50 • Celestial Photography

CELESTIAL PHOTOGRAPHY

After looking at the night sky for awhile you may want to try photographing it.

Several forms of celestial photography are possible with your Celestron CM-

1100 telescope. The most common forms of celestial photography, in order of

difficulty are; short exposure prime focus, piggyback, eyepiece projection, and

long exposure deep-sky. Each of these is discussed in moderate detail with

enough information to get you started. Topics include the accessories required

and some simple techniques. More information is available in some of the

publications listed at the end of this manual.

In addition to the specific accessories required for each type of celestial

photography, there is the need for a camera — but not just any camera. The

camera does not need many of the features offered on today’s state-of-the-art

equipment. For example, you don’t need auto focus capability or mirror lock-

up. Here are the mandatory features a camera needs for celestial photogra-

phy. First, a ‘B’ setting which allows for time exposures. This excludes point

and shoot cameras and limits the selection to SLR cameras, the most com-

mon type of 35mm camera on the market today.

Second, the ‘B’ or manual setting should not run off the battery. Many new

electronic cameras use the battery to keep the shutter open during time

exposures. Once the batteries are drained, usually after a few minutes, the

shutter closes, whether you were finished with the exposure or not. Look for a

camera that has a manual shutter when operating in the time exposure mode.

Olympus, Nikon, Minolta, Pentax and others have made such camera bodies.

The camera should have interchangeable lenses so you can attach it to the

telescope and so you can use a variety of lenses for piggyback photography. If

you can’t find a new camera, you can purchase a used camera body that is

not 100-percent functional. The light meter does not have to be operational

since you will be determining the exposure length manually.

A cable release is needed with a locking function to hold the shutter open while

you do other things. Mechanical and air releases are available.

Is unguided astrophotography possible? Yes and no. For solar (filtered), lunar,

and piggyback (up to 200mm telephotos), the answer is yes. However, even

with PEC, off-axis guiding is still mandatory for long exposure, deep-sky

astrophotography. The Reducer/Corrector lens reduces exposure times

making the task of guiding a little easier.

Celestial Photography • 51

Short exposure prime focus photography is the best way to begin recording

celestial objects. It is done with the camera attached to the telescope without

an eyepiece or camera lens in place. To attach your camera you need the

Celestron T-Adapter (#93633-A) and a T-Ring for your specific camera (i.e.,

Minolta, Nikon, Pentax, etc.). The T-Ring replaces the 35mm SLR camera’s

normal lens. Prime focus photography allows you to capture the majority of

the solar disk (if using the proper filter) as well as the Moon. To attach your

camera to your CM-1100:

1. Remove all visual accessories.

2. Thread the T-Ring onto the T-Adapter.

3. Mount your camera body onto the T-Ring the same as you would any other

lens.

4. Thread the T-Adapter onto the back of the Celestron CM-1100 while

holding the camera in the desired orientation (either vertical or horizontal).

With your camera attached to the telescope, you are ready for prime focus

photography. Start with an easy object like the Moon. Here’s how to do it:

1. Load your camera with film that has a moderate-to-fast speed (i.e., ISO

rating). Faster films are more desirable when the Moon is a crescent.

When the Moon is near full, and at its brightest, slower films are more

desirable. Here are some film recommendations:

• T-Max 100

• T-Max 400

• Any 100 to 400 ISO color slide film

• Fuji Super HG 400

2. Center the Moon in the field of your CM-1100

3. Focus the telescope by turning the focus knob until the image is sharp.

4. Set the shutter speed to the appropriate setting (see the table below).

5. Trip the shutter using a cable release.

6. Advance the film and repeat the process.

Short Exposure

Prime Focus

Lunar Phase ISO 50 ISO 100 ISO 200 ISO 400

Crescent 1/2 1/4 1/8 1/15

Quarter 1/15 1/30 1/60 1/125

Full 1/30 1/60 1/125 1/125

Table 7-1

Above is a listing of recommended exposure times when photographing the

Moon at the prime focus of your Celestron CM-1100 telescope.

52 • Celestial Photography

The exposure times listed here should be used as a starting point. Always

make exposures that are longer and shorter than the recommended time.

Also, try bracketing your exposures, taking a few photos at each shutter

speed. This will ensure that you will get a good photo.

Keep accurate records of your exposures. This information is useful if you

want to repeat your results or if you want to submit some of your photos to

various astronomy magazines for possible publication!

This same technique is used for photographing the Sun with the proper solar

filter.

Celestial Photography • 53

The easiest way to enter the realm of deep-sky, long exposure astrophotogra-

phy is via the piggyback method. Piggyback photography is done with a

camera and its normal lens riding on top of the telescope. Through piggyback

photography you can capture entire constellations and record large scale

nebulae that are too big for prime focus photography. Because you are

photographing with a low power lens and guiding with a high power telescope,

the margin for error is very large. Small mistakes made while guiding the

telescope will not show up on film. Use the optional piggyback mount to attach

the camera to the telescope.

As with any form of deep-sky photography, you must be at a dark sky observ-

ing site. Light pollution around major urban areas washes out the faint light of

deep-sky objects.

1. Polar align the telescope (using one of the methods described earlier) and

start the clock drive.

2. Load your camera with slide film, ISO 100 or faster, or print film, ISO 400

or faster!

3. Set the f/ratio of your camera lens so that it is a half stop to one full stop

down from completely open.

4. Set the shutter speed to the “B” setting and focus lens to infinity setting.

5. Locate the area of the sky that you want to photograph and move the

telescope so that it points in that direction.

6. Find a suitable guide star in the telescope field. This is relatively easy

since you can search a wide area without affecting the area covered by

your camera lens. If you do not have an illuminated cross hair eyepiece for

guiding, simply defocus your guide star until it fills most of the field of view.

This makes it easy to detect any drift.

7. Release the shutter using a cable release.

8. Monitor your guide star for the duration of the exposure. Make all correc-

tions using the hand controller.

9. Close the camera’s shutter.

As for lenses, get good ones that produce sharp images near the edge of the

field. Generally, stay away from generic lenses. The lenses should have a

resolving power of 40 lines per millimeter. A good focal length range is 35 to

100mm for lenses designed for 35mm cameras.

Piggyback

54 • Celestial Photography

The exposure time depends on the film being used. However, five minutes is

usually a good starting point. With slower films, like 100 ISO, you can expose

as long as 45 minutes. With faster films, like 1600 ISO, you really shouldn’t

expose more than 5 to 10 minutes. When getting started, use fast films to

record as much detail in the shortest possible time. Here are proven recom-

mendations:

• Ektar 1000 (color print)

• Konica 3200 (color print)

• Fujichrome 1600D (color slide)

• 3M 1000 (color slide)

• T-Max 3200 (black and white print)

• T-Max 400 (black and white print)

As you perfect your technique, try specialized films (i.e., specially designed

and/or treated) for this type of astrophotography. Here are some popular

choices:

• Ektar 125 (color print)

• Fujichrome 100D (color slide)

• Tech Pan, gas hypered (black and white print)

• T-Max 400 (black and white print)

As with all forms of photography, keep accurate records of your work. This

information can be used later if you want to reproduce certain results or if you

want to submit photos for possible publication.

Once you have mastered piggyback photography with wide angle and normal

lenses, try longer focal length lenses. The longer the focal length, the more

accurate your guiding must be. You can continue to increase the focal length

of the lens until you are ready for prime focus photography with your Celestron

CM-1100

Celestial Photography • 55

This form of celestial photography is designed for objects with small angular

sizes, primarily the Moon and planets. Planets, although physically quite

large, appear small in angular size because of their great distances. Moderate

to high magnification is, therefore, required to make the image large enough to

see any detail. Unfortunately, the camera/telescope combination alone does

not provide enough magnification to produce a usable image size on film. In

order to get the image large enough, you must attach your camera to the

telescope with the eyepiece in place. To do so, you need two additional

accessories; a Deluxe Tele-Extender (#93643), which attaches onto the visual

back, and a T-ring for your particular camera make (i.e., Minolta, Nikon,

Pentax, etc.).

Because of the high magnifications during eyepiece projection, the field of view

is quite small which makes it difficult to find and center objects. To make the

job a little easier, align the finder as accurately as possible. This allows you to

get the object in the field based on the finder view alone.

Another problem introduced by the high magnification is vibration. Simply

tripping the shutter — even with a cable release — produces enough vibration

to smear the image. To get around this, use the camera’s self-timer if the

exposure time is less than one second — a common occurrence when

photographing the Moon. For exposures over one second, use the “hat trick.”

This technique incorporates a hand-held black card placed over the aperture of

the telescope to act as a shutter. The card prevents light from entering the

telescope while the shutter is released. Once the shutter has been released

and the vibration has diminished (a few seconds), move the black card out of

the way to expose the film. After the exposure is complete, place the card

over the front of the telescope and close the shutter. Advance the film and

you’re ready for your next shot. Keep in mind that the card should be held a

few inches in front of the telescope, and not touching it. It is easier if you use

two people for this process; one to release the camera shutter and one to hold

the card. Here’s the process for making the exposure.

1. Find and center the desired target in the viewfinder of your camera.

2. Turn the focus knob until the image is as sharp as possible.

3. Place the black card over the front of the telescope.

4. Release the shutter using a cable release.

5. Wait for the vibration caused by releasing the shutter to diminish. Also,

wait for a moment of good seeing.

6. Remove the black card from in front of the telescope for the duration of the

exposure (see accompanying table).

7. Replace the black card over the front of the telescope.

8. Close the camera’s shutter.

Advance the film and your ready for your next exposure. Don’t forget to take

photos of varying duration and keep accurate records of what you have done.

Record the date, telescope, exposure duration, eyepiece, f/ratio, film, and

some comments on the seeing conditions.

Eyepiece Projection

56 • Celestial Photography

The following table lists exposures for eyepiece projection with a 10mm

eyepiece. All exposure times are listed in seconds or fractions of a second.

The exposure times listed here should be used as a starting point. Always

make exposures that are longer and shorter than the recommended time.

Also, try bracketing your exposures, taking a few photos at each shutter

speed. This will ensure that you will get a good photo. It is not uncommon to

go through an entire roll of 36 exposures and have only one shot turn out good.

Don’t expect to record more detail than you can see visually in the eyepiece at

the time you are photographing.

Once you have mastered the technique, experiment with different films,

different focal length eyepieces, and even different filters.

Planet ISO 50 ISO 100 ISO 200 ISO 400

Moon 4211/2

Mercury 16842

Venus 1/2 1/4 1/8 1/15

Mars 16842

Jupiter 8421

Saturn 16842

Table 7-2

Celestial Photography • 57

This is the last form of celestial photography to be attempted after others have

been mastered. It is intended primarily for deep-sky objects, that is objects

outside our solar system which includes star clusters, nebulae, and galaxies.

While it may seem that high magnification is required for these objects, just

the opposite is true. Most of these objects cover large angular areas and fit

nicely into the prime focus field of your Celestron CM-1100 telescope. The

brightness of these objects, however, requires long exposure times and, as a

result, are rather difficult.

There are several techniques for this type of photography, and the one chosen

will determine the standard accessories needed. If, for example, you use a

separate guidescope, the camera attaches to the telescope with a T-Adapter

(#93633-A) and a T-Ring for your specific camera. However, the best method

for long exposure deep-sky astrophotography is with an off-axis guider. This

devise allows you to photograph through the telescope and guide simulta-

neously. Celestron offers a very special and advanced off-axis guider, called

the Radial Guider (#94176). In addition, you will need a T-Ring to attach your

camera to the Radial Guider.

Other equipment needs include a guiding eyepiece. Unlike piggyback photog-

raphy which allows for fairly loose guiding, prime focus requires meticulous

guiding for long periods. To accomplish this you need a guiding ocular with an

illuminated reticle to monitor your guide star. For this purpose, Celestron

offers the Micro Guide Eyepiece (#94171). Here is a brief summary of the

technique.

1. Polar align the telescope using the declination drift method.

2. Remove all visual accessories.

3. Thread the Radial Guider onto your Celestron CM-1100.

4. Thread the T-Ring onto the Radial Guider.

5. Mount your camera body onto the T-Ring the same as you would any other

lens.

6. Set the shutter speed to the “B” setting.

7. Focus the telescope on a star.

8. Center your subject in the field of your camera.

9. Find a suitable guide star in the telescope field. This can be the most time

consuming process.

10. Open the shutter using a cable release.

11. Monitor your guide star for the duration of the exposure.

12. Close the camera’s shutter.

Long Exposure

Prime Focus

58 • Celestial Photography

When getting started, use fast films to record as much detail in the shortest

possible time. Here are proven recommendations:

• Ektar 1000 (color print)

• Konica 3200 (color print)

• Fujichrome 1600D (color slide)

• 3M 1000 (color slide)

• T-Max 3200 (black and white print)

• T-Max 400 (black and white print)

As you perfect your technique, try specialized films (i.e., specially designed

and/or treated) for this type of astrophotography. Here are some popular

choices:

• Ektar 125 (color print)

• Fujichrome 100D (color slide)

• Tech Pan, gas hypered (black and white print)

• T-Max 400 (black and white print)

There is no exposure determination table to help you get started. The best

way to determine exposure length is look at previously published photos to see

what film/exposure combination was used. Or take unguided sample photos of

various parts of the sky while the drive is running. Take exposures of various

lengths to determine the best exposure time.

Celestial Photography • 59

Fastar Lens Assembly Option – Using your CM-1400 telescope at f/2.1 with

optional PixCel CCD Camera

Only the CM-1400 is equipped with a removable secondary mirror that allows

you to convert your f/11 telescope into an f/2.1 imaging system capable of

exposure times 25 times shorter than those needed with a f/11 system! Used with

Celestron’s PixCel CCD System, objects will be easily found due to the wide .36°

by .27° field of view provided. With the optional Fastar lens assembly you can

easily convert your Fastar compatible telescope to f/2.1 prime focus use in a matter

of seconds. Your telescope can now be used in many different f-number’s for CCD

imaging. It can be used at f/2.1 (with optional Fastar Lens Assembly), f/7 (with the

optional Reducer/Corrector), f/11, and f/22 (with the optional 2x barlow) making it

the most versatile imaging system available today. This makes the system ideal

for imaging deep-sky objects as well as planetary detail. The key to the Fastar’s

versatility is the variety of different F-numbers in which it can be used. Described

below is the significance of each F-number and the type of object best suited to

that kind of imaging.

The above figure shows how the secondary mirror is removed when using the

optional PixCel CCD camera at f/2.1 and the Fastar Lens Assembly (#94181).

Warning: The secondary mirror should never be removed unless installing the

optional Fastar Lens Assembly. Adjustments to collimation can easily be

made by turning the screws on the top of the secondary mirror mount without

ever having to remove the secondary mirror (see Telescope Maintenance

section of this manual).

Secondary

Mirror

Secondary

Mirror

Retaining Ring

Corrector Plate

Secondary

Mirror Mount

Handle

Figure 7-1

CCD IMAGING

60 • Celestial Photography

The F/# stands for the ratio between the focal length and the diameter of the

light gathering element. A C14 optical tube has a focal length of 154 inches

and a diameter of 14 inches. This makes the system an f/11, (focal length

divided by diameter). When the secondary is removed and the CCD is placed

at the Fastar position, the system becomes f/2.1, this is unique to Celestron

telescopes (see figures below).

The following is a brief description of the advantages of imaging at each f-

number configuration and the proper equipment needed to use the telescope in

any of its many settings. Refer to Figure 7-6 for a more detailed description of

the accessories offered for each configuration.

Fastar Lens Assembl

PixCel 237 CCD Camera

Table 7-3

Figure 7-2 -- Light path at f/11 focus Figure 7-3 -- Light path at Fastar f/2.1 focus

Description of

F-numbers

Fastar Configuration

Standard Cassegrain With Reducer/Corrector With Fastar Lens

Accessory Accessory

Focal Length & Speed 154"(3910mm) @ f/11 98" (2488mm) @ f/7 29.4" (747mm) @ f/2.1

PixCel 237 F.O.V. 4.1 x 3.2 (arc min) 6.5 x 5 (arc min) 22 x 17 (arc min)

The key factors for good CCD imaging are; exposure time, field-of-view, image

size, and pixel resolution. As the F/# goes down (or gets faster), the exposure

times needed decreases, the field-of-view-increases, but the image scale of the

object gets smaller. What is the difference between f/2.1 and f/11? F/2.1 has

1/5 the focal length of f/11. That makes the exposure time needed about 25

times shorter than at f/11, the field of view 5 times larger and the object size

1/5 compared to that of f/11. (see Table below)

Celestial Photography • 61

When imaging some objects like planetary nebula (for example M57, the Ring

Nebula) and small galaxies (M104, the Sombrero Galaxy), larger image scale

is needed to resolve finer detail. These objects are better shot at f/7 or even f/

11.

Medium size to small galaxies --

f/7 imaging gives you finer resolution then at f/2.1, but the slower f-number will

usually require you to guide the image while you are taking longer exposures.

Guiding can be accomplished by using an optional Radial Guider or a piggyback

guidescope. The exposure times are about 10 times longer but the results can be

worth the extra effort. There are some objects that are small enough and bright

enough that they work great at f/7. M104 (the Sombrero Galaxy) can be imaged

under dark skies with a series of short exposures using Track and Accumulate.

Ten exposures at 15 seconds each will yield a nice image and is short enough that

you may not need to guide the exposure at all. For f/7 imaging the optional

Reducer/Corrector is needed. (See Optional Accessory section at the end of this

manual).

Lunar or small planetary nebulae--

f/11 imaging is more challenging for long exposure, deep-sky imaging. Guiding

needs to be very accurate and the exposure times need to be much longer,

about 25 times longer than f/2.1. There are only a select few objects that

work well at f/11. The moon images fine because it is so bright, but planets

are still a bit small and should be shot at f/22. The Ring nebula is a good

candidate because it is small and bright. The Ring Nebula (M57) can be

imaged in about 30-50 seconds at f/11. The longer the exposure the better.

As stated above, the exposure times are much shorter at f/2.1 than at f/7 or

f/11. The field-of-view is wider, so it is easier to find and center objects. Also

with a wider field-of-view you can fit larger objects (such as M51, The Whirlpool

Galaxy) in the frame. Typical exposure times can be 20-30 seconds for many

objects. With the Track and Accumulate function on the PixCel software (see

the PixCel Operating Manual for more details about its software features), the

camera can shoot and stack several images automatically without ever having

to guide the exposure. Under dark skies you can get an excellent image of the

Dumbbell Nebula (M27) with only a few 30 second exposures (see figure 7-4

below). The spiral arms of the Whirlpool galaxy (Figure 7-5) can be captured

with a 30 second exposure and can be improved upon dramatically if several

30-60 second exposures are added together using the Track and Accumu-

late™ feature.

Imaging at f/2.1

Imaging at f/11

Imaging at f/7

Figure 7-4 M27 -- The Dumbbell Nebula

4 exposures of 30 seconds each! Figure 7-5 M51 -- The Whirlpool Nebula

9 exposures of 60 seconds each.

62 • Celestial Photography

Planetary or Lunar--

f/20 is a great way to image the planets and features on the moon. With the

PixCel CCD camera and optional Color Filter Wheel, it is easy to take tri-color

images of planets also. When imaging the planets, very short exposures are

needed. Many cameras have trouble taking images under .1 seconds. The

PixCel camera can image at .01 seconds exposures due to the design of the

CCD array. The exposure lengths range from .03 to .1 seconds on planetary

images. Focus is critical as is good atmospheric conditions. Generally you

will take one image after another until one looks good (see AutoGrab feature in

the PixCel Operating Manual). This is due to the atmospheric “seeing” condi-

tions. For every 10 exposures you might save 1. To image at f/22 you need to

purchase a 2x Barlow and a T-adapter or Radial Guider.

1 Optical Tube Assembly 13 Radial Guider

2 Secondary Mirror 14 Microguide Eyepiece

3 Secondary Mirror Retaining Ring 15 Illuminator (Microguide Eyepiece only)

4 Fastar Lens Spacer 16 Pulstar Illuminator

5 Fastar Spacer Retaining Ring 17 Visual Back 1 ¼”

6 Fastar Lens Assembly 18 Star Diagonal

7 Tricolor Spacer Ring 19 2X Barlow Lens

8 Fastar 14 T-Adapter 20 Cross Hair Eyepiece

9 IR Cutoff Filter 21 26mm Plossl Eyepiece

10 PixCel CCD Camera 22 T-Ring

11 Reducer/Corrector f/6.3 23 T - 1 1/4" Adapter

12 T-Adapter 24 35mm SLR Camera

Imaging at f/22

Figure 7-6 -- This diagram shows the many accessories that can be used with the Fastar compatible

CM-14 telescope in its various optical configurations.

Telescope Maintenance • 63

TELESCOPE MAINTENANCE

While your CM-1100 telescope requires little maintenance, there are a few

things to remember that will ensure your telescope performs at its best.

Occasionally, dust and/or moisture may build up on the corrector plate of your

telescope. Special care should be taken when cleaning any instrument so as

not to damage the optics.

If dust has built up on the corrector plate, remove it with a brush (made of

camel’s hair) or a can of pressurized air. Spray at an angle to the lens for

approximately two to four seconds. Then, use an optical cleaning solution and

white tissue paper to remove any remaining debris. Apply the solution to the

tissue and then apply the tissue paper to the lens. Low pressure strokes

should go from the center of the corrector to the outer portion. Do NOT rub in

circles!

You can use a commercially made lens cleaner or mix your own. A good

cleaning solution is isopropyl alcohol mixed with distilled water. The solution

should be 60% isopropyl alcohol and 40% distilled water. Or, liquid dish soap

diluted with water (a couple of drops per one quart of water) can be used.

Occasionally, you may experience dew build-up on the corrector plate of your

telescope during an observing session. If you want to continue observing, the

dew must be removed, either with a hair dryer or by pointing the telescope at

the ground until the dew has evaporated.

If moisture condenses on the inside of the corrector, remove the accessories

from the rear cell of the telescope. Place the telescope in a dust-free environ-

ment and point it down. This will remove the moisture from the telescope tube.

To minimize the need to clean your telescope, replace all lens covers once you

have finished using it. Since the rear cell is NOT sealed, the cover should be

placed over the opening when not in use. This will prevent contaminants from

entering the optical tube.

Internal adjustments and cleaning should be done only by the Celestron repair

department. If your telescope is in need of internal cleaning, please call the

factory for a return authorization number and price quote.

The optical performance of your Celestron CM-1100 telescope is directly

related to its collimation, that is the alignment of its optical system. Your

Celestron CM-1100 was collimated at the factory after it was completely

assembled. However, if the telescope is dropped or jarred severely during

transport, it may have to be collimated. The only optical element that may

need to be adjusted, or is possible, is the tilt of the secondary mirror.

To check the collimation of your telescope you will need a light source. A

bright star near the zenith is ideal since there is a minimal amount of atmo-

Care and Cleaning

of the Optics

Collimation

64 • Telescope Maintenance

spheric distortion. Turn your telescope drive on so that you won’t have to

manually track the star. Or, if your are not using the clock drive, use Polaris.

Its position relative to the celestial pole means that it moves very little thus

eliminating the need to manually track it.

Before you begin the collimation process, be sure that your telescope is in

thermal equilibrium with the surroundings. Allow 45 minutes for the telescope

to reach equilibrium if you move it between large temperature extremes.

To verify collimation, view a star near the zenith. Use a medium to high power

ocular — 12mm to 6mm focal length. It is important to center a star in the

center of the field to judge collimation. Slowly cross in and out of focus and

judge the symmetry of the star. If you see a systematic skewing of the star to

one side, then recollimation is needed.

Figure 8-1 -- Even though the star pattern appears the same on both sides of focus,

they are asymmetric. The dark obstruction is skewed off to the left side of the

diffraction pattern indicating poor collimation.

To accomplish this, you need to tighten the secondary collimation screw(s)

that move the star across the field toward the direction of the skewed light.

These screws are located in the secondary mirror holder. Make only a small

1/6 to 1/8 field correction and recenter the star by moving the scope before

making any improvements or before making further adjustments.

To make collimation a simple procedure, follow these easy steps:

1 While looking through a medium to high power eyepiece, de-focus a

bright star until a ring pattern with a dark shadow appears (see figure

8-1). Center the de-focused star and notice in which direction the

central shadow is skewed.

2 Place your finger (or the finger of a friend) along the edge of the front

cell of the telescope, pointing towards the collimation screws. the

shadow of your finger should be visible when looking into the eyepiece.

Rotate your finger around the tube edge until its shadow is seen

closest to the narrowest portion of the rings (ie. the same direction in

which the central shadow is skewed).

3 Locate the collimation screw closest to where your finger is posi-

tioned. This will be the collimation screw you will need to adjust first.

(If your finger is positioned exactly between two of the collimation

screws, then you will need to adjust the screw opposite where your

finger is located).

4 Use the slow motion controls to move the de-focused star image to the

edge of the field of view, in the same direction that the central obstruc-

tion of the star image is skewed.

Telescope Maintenance • 65

6 Once the star image is in the center of the field of view, check to see if

the rings are concentric. If the central obstruction is still skewed in

the same direction, then continue turning the screw(s) in the same

direction. If you find that the ring pattern is skewed in a different

direction, than simply repeat steps 2 through 6 as described above for

the new direction.

Perfect collimation will yield a star or planetary image very symmetrical just

inside and outside of focus. In addition, perfect collimation delivers the optimal

optical performance specifications that your telescope is built to achieve.

If seeing (i.e., air steadiness) is turbulent, collimation is difficult to judge. Wait

until a better night if it is turbulent or aim to a steadier part of the sky. A

steadier part of the sky is judged by steady versus twinkling stars.

5 While looking through the eyepiece, use a screwdriver to turn the

collimation screw you located in step 2 and 3. Usually a tenth of a

turn is enough to notice a change in collimation. If the star image

moves out of the field of view in the direction that the central shadow is

skewed, than you are turning the collimation screw the wrong way.

Turn the screw in the opposite direction, so that the star image is

moving towards the center of the field of view.

If while turning you notice that the screws get very loose, than simply tighten

the other two screws by the same amount. Conversely, if the collimation

screw gets too tight, then loosen the other two screws by the same amount.

Figure 8-2

A collimated telescope

should appear symmetrical

with the central obstruction

centered in the star's

diffraction pattern.

66 • Optional Accessories

OPTIONAL ACCESSORIES

The following is a partial list of optional accessories available for your Celestron

CM-1100/1400. You will find that additional accessories enhance your viewing

pleasure and expand the usefulness of your telescope. For ease of reference,

all the accessories are listed in alphabetical order.

AC Adapter - 110V - 60Hz (#18770) - The AC Adapter allows you to run your

CM telescope off of AC rather than the standard DC battery.

Advanced Astro Master (#93900) - This unique accessory contains a data

base of more than 10,000 objects! Included are the Messier catalog, NGC

catalog, IC catalog, portions of the ESO catalog, portions of the UGC catalog,

special non-stellar catalog which contains objects not found in any of the other

catalogs, a star catalog containing 241 interesting double and multiple stars,

and a user definable catalog that allows you to enter 25 of your favorite objects.

And, scrolling information cross references Sky Atlas 2000.0 or Uranometria .

Unlike other digital setting circles, which require the use of a clock drive, the

Advanced Astro Master can be used with or without a clock drive. All you have

to do is align on any two of the 28 navigational alignment stars in the Advanced

Astro Master’s data base and you are ready to observe. Once aligned, the

system keeps track of where it is pointed. And, the Advanced Astro Master

has an RS-232 port for complete interface to your personal computer. The RS-

232 cable (#93921) is available. The encoder installation kit for the CI-700

mount is #93908.

Barlow Lenses - A Barlow lens is a negative lens that increases the focal

length of a telescope. Used with any eyepiece, it doubles the magnification of

that eyepiece. Celestron offers two Barlow lenses in the 1-1/4" size. The 2x

Ultima Barlow (#93506) is a compact triplet design that is fully multicoated for

maximum light transmission and parfocal when used with the Ultima eye-

pieces. It works very well with all Celestron eyepieces. The latest Barlow to

be added to Celestron’s product line (#93507) is a low profile achromatic

design. It weighs just 4 oz. and it is under 3" in length.

Counterweight - 11 lbs. - Extra counterweights (#94195) may be necessary

when using heavy accessories.

2” Mirror Diagonal (#93519) -For the CM-1100 (Standard on CM-1400). Like

the l-l/4" Prism Star Diagonals, the 2" Mirror Diagonal allows you to use 2"

eyepieces with your Celestron telescope. These larger eyepieces offer wider

fields and better eye relief for greater viewing comfort. This accessory is NOT

recommended for use with the Reducer/Corrector Lens.

Erect Image Diagonal (#94112-A) - For daytime terrestrial viewing the Erect

Image Diagonal produces images through your Schmidt-Cassegrain telescope

that match what you see with the unaided eye. This accessory uses an Amici

Optional Accessories • 67

prism arrangement that, in addition to producing correctly oriented images,

allows you to look into the telescope at a 45° angle, a desirable arrangement

for terrestrial viewing.

Eyepiece Filters - To enhance your visual observations of planetary objects,

Celestron offers a wide range of colored filters that thread into the 1-1/4"

oculars. Available are: #12 Deep Yellow, #21 Orange, #25 Red, #58 Green,

#80A Light Blue, #96 Neutral Density (25% T, and 13% T) and Polarizing

filters. These and other filters are also sold in sets.

Eyepieces - Like telescopes, eyepieces come in a variety of designs. And,

with the advent of different eyepieces, Celestron also has a variety of designs

each with its own advantages and disadvantages. For the 1-1 /4" barrel

diameter there are four different eyepiece designs available.

•SMA - The SMA design is an improved version of the Kellner eyepiece.

SMA’s are very good, economical, general purpose eyepieces. Available in

focal lengths of 6mm, 10mm, 12mm, and 25mm.

•Plossl - Plossl eyepieces have a 4-element lens designed for low-to-high

power observing. The Plossls offer razor sharp views across the entire field,

even at the edges! In the 1-1 /4" barrel diameter, they are available in the

following focal lengths: 6.3mm, 7.5mm, 10mm, 12.5mm, 17mm, 20mm,

26mm, 32mm, and 40mm.

•Ultima - Ultima is not really a design, but a trade name for our 5-element,

wide field eyepieces. In the 1-1/4" barrel diameter, they are available in the

following focal lengths: 5mm, 7.5mm, 12.5mm, 18mm, 24mm, 30mm, 35mm,

and 42mm. These eyepieces are all parfocal. The 35mm Ultima gives the

widest possible field of view with a 1-1 /4" diagonal and is ideal for use with the

Reducer/Corrector.

•Lanthanum Eyepieces (LV Series) - Lanthanum is a unique rare earth glass

used in one of the field lenses of this new eyepiece. The Lanthanum glass

reduces aberrations to a minimum. All are fully multicoated and have an

astounding 20mm of eye relief—perfect for eyeglass wearers! In the 1-1/4"

barrel diameter, they are available in the following focal lengths: 2.5mm, 4mm,

5mm, 6mm, 9mm, 10mm, 12mm, 15mm, 20mm and 25mm. Also available is

an LV Zoom Eyepiece with the focal length range of 8 to 24 mm.

In addition to the previously mentioned, there is also a deluxe compact zoom

ocular (#93306) that has a variable focal length of 6.5 to 18mm.

Finderscopes - Finderscopes are used to help you locate objects in the main

telescope. The larger the finderscope, the more you will see, making it easier

to locate objects. One option for finders is the illuminated Polaris 7x50 Finder

(#93785-8P). It comes with the bracket, finderscope, and illuminator. There is

also a Quick Release Finder bracket (#51149-A) which allows you to easily

remove and replace the finderscope without losing alignment. The Quick

Release Bracket is only available for the 9x50 and 7x50 Finderscopes.

Another tool for finding objects in the sky is the Star Pointer (#51630). The

Star Pointer is different from a finderscope in that you can use both eyes when

pointing the telescope at an object. A partially reflective surface projects the

image of an LED illuminated pinpoint into the line of sight. Just align the

illuminated pinpoint with the object you are interested in and the object will be

68 • Optional Accessories

in the main telescope.

Flashlight (#93592) - The LED flashlight uses a red LED to allow reading star

maps without ruining your night vision. The LED flashlight is small, only 6

inches long, and weighs in at a mere 3 ounces.

Flashlight, Night Vision (#93588) - Celestron’s premium model for as-

tronomy, using two red LEDs to preserve night vision. The brightness is

adjustable and it operates on a single 9 Volt battery.

Light Pollution Reduction (LPR) Filters - These filters are designed to

enhance your views of deep-sky astronomical objects when viewed from urban

areas. LPR Filters selectively reduce the transmission of certain wavelengths

of light, specifically those produced by artificial lights. This includes mercury

and high and low pressure sodium vapor lights. In addition, they also block

unwanted natural light (sky glow) caused by neutral oxygen emission in our

atmosphere. Celestron offers a model for 1-l/4" eyepieces (#94126A) and a

model that attaches to the rear cell ahead of the star diagonal and visual back

(#94127A).

Micro Guide Eyepiece (#94171) - This multipurpose illuminated 12.5mm

reticle can be used for guiding deep-sky astrophotos, measuring position

angles, angular separations, and more. The laser etched reticle provides razor

sharp lines and the variable brightness illuminator is completely cordless.

Piggyback Mount (#93598) - The best way to enter the realm of deep-sky

photography is via the piggyback method. Piggyback photography allows you

to record constellations and large scale nebulae that don’t fit in the field of your

telescope. The piggyback mount allows you to attach a camera to the top of

the telescope. This way, the camera can photograph with its normal or wide

angle lens while you guide through the telescope. The piggyback mount

attaches to the rear cell of the telescope next to the finder.

Polarizing Filter Set (#93608) - The polarizing filter set limits the transmis-

sion of light to a specific plane, thus increasing contrast between various

objects. This is used primarily for terrestrial, lunar, and planetary observing.

Radial Guider (#94176) - The Celestron Radial Guider is specifically designed

for use in prime focus, deep-sky astrophotography and takes the place of the

T-Adapter. This device allows you to photograph and guide simultaneously

through the optical tube assembly of your telescope. This type of guiding

produces the best results since what you see through the guiding eyepiece is

exactly reproduced on the processed film. The Radial guider is a “T”-shaped

assembly that attaches to the rear cell of the telescope. As light from the

telescope enters the guider, most passes straight through to the camera. A

small portion, however, is diverted by a prism at an adjustable angle up to the

guiding eyepiece. This guider has two features not found on other off-axis

guiders; first, the prism and eyepiece housing rotate independently of the

camera orientation making the acquisition of a guide star quite easy. Second,

the prism angle is tunable allowing you to look at guide stars on-axis. This

accessory works especially well with the Reducer/Corrector.

Reducer/Corrector (#94175) - This lens reduces the focal length of the

telescope by 37%, making your CM-1100 a l,764mm f/6.3 instrument. In

addition, this unique lens also corrects inherent aberrations to produce crisp

images all the way across the field. It also increases the field of view signifi-

cantly and is ideal for wide-field, deep-sky viewing. It is perfect for beginning

Optional Accessories • 69

prime focus long-exposure astrophotography. It makes guiding easier and

exposures shorter.

Sky Maps (#93722) - When learning the night sky, the Celestron Sky Maps

offer the ideal solution. The maps include all the constellations and brighter

deep-sky objects. The maps are printed on a heavy stock paper that is

moisture-resistant. On the front cover is a rotating planisphere which indicates

when specific constellations are visible.

Skylight Filter (#93621) - The Skylight Filter is used on Celestron Schmidt-

Cassegrain telescopes as a dust seal. The filter threads onto the rear cell of

your telescope. All other accessories, both visual and photographic, thread

onto the Skylight Filter. Although it does cut down on a portion of the incom-

ing light, it is a very small amount. It should be noted, that most Barlow lenses

can NOT be inserted into the visual back when the skylight filter is attached.

T-Adapter (#93633-A) - A T-Adapter (with T-Ring) allows you to attach your

camera to the prime focus of a Celestron Schmidt-Cassegrain telescope. This

is used for terrestrial photography and short exposure lunar and filtered solar

photography. It can be used for long exposure deep-sky photography if you

use a separate guidescope.

T-C Adapter (#93636) - This adapter allows you to couple a video or movie

camera to a telescope. The camera must have a removable lens with a

standard “C” thread. The T-C adapter threads into the camera and then onto

the T-Adapter.

T-Ring - The T-Ring couples your camera body to the T-Adapter, Radial Guider

Body, or Tele-Extender. This accessory is mandatory if you want to do astro-

photography through the telescope. Each camera make (i.e., Minolta, Nikon,

etc.) has its own unique mount and therefore, its own T-Ring.

Tele-Extender, Deluxe (#93643) - The tele-extender is a hollow tube that

allows you to attach a camera to the telescope when the eyepiece is installed.

This accessory is used for eyepiece projection photography which allows you

to capture very high power views of the Sun, Moon, and planets on film. The

tele-extender fits over the eyepiece onto the visual back and works with

eyepieces that have large housings, like the Celestron Ultima series.

A full description of all Celestron accessories can be found in the

Celestron Accessory Catalog (#93685).

70 • The Messier Catalog

THE MESSIER CATALOG

The Messier Catalog, compiled by Charles Messier, was the first extensive listing of star clusters and nebulae.

Messier’s primary observational purpose was to discover comets. He compiled this list so that others searching

for comets would not be confused by these objects. His list still remains popular today because all of these

objects are easily visible in amateur telescopes.

M# NGC# Const. R.A. DEC Mag Type Proper Name

H M S ° ‘

M1 NGC 1952 Tau 5 34.5 22 01 8.4 P. Neb. Crab Nebula

M2 NGC 7089 Aqr 21 33.5 -00 49 6.5 Gl. Cl.

M3 NGC 5272 CVn 13 42.2 28 23 6.4 Gl. Cl.

M4 NGC 6121 Sco 16 23.6 -26 32 5.9 Gl. Cl.

M5 NGC 5904 Ser 15 18.5 2 05 5.8 Gl. Cl.

M6 NGC 6405 Sco 17 40.0 -32 13 4.2 Op. Cl. Butterfly Cluster

M7 NGC 6475 Sco 17 54.0 -34 49 3.3 Op. Cl.

M8 NGC 6523 Sgr 18 03.7 -24 23 5.8 D. Neb. Lagoon Nebula

M9 NGC 6333 Oph 17 19.2 -18 31 7.9 Gl. Cl.

M10 NGC 6254 Oph 16 57.2 -4 06 6.6 Gl. Cl.

M11 NGC 6705 Sct 18 51.1 -6 16 5.8 Op. Cl. Wild Duck Cluster

M12 NGC 6218 Oph 16 47.2 -1 57 6.6 Gl. Cl.

M13 NGC 6205 Her 16 41.7 36 28 5.9 Gl. Cl. Hercules Cluster

M14 NGC 6402 Oph 17 37.6 -3 15 7.6 Gl. Cl.

M15 NGC 7078 Peg 21 30.0 12 10 6.4 Gl. Cl.

M16 NGC 6611 Ser 18 18.9 -13 47 6.0 D. Neb. Eagle Nebula

M17 NGC 6618 Sgr 18 20.8 -16 11 7.0 D. Neb. Omega Nebula

M18 NGC 6613 Sgr 18 19.9 -17 08 6.9 Op. Cl.

M19 NGC 6273 Oph 17 02.6 -26 16 7.2 Gl. Cl.

M20 NGC 6514 Sgr 18 02.4 -23 02 8.5 D. Neb. Trifid Nebula

M21 NGC 6531 Sgr 18 04.7 -22 30 5.9 Op. Cl.

M22 NGC 6656 Sgr 18 36.4 -23 54 5.1 Gl. Cl.

M23 NGC 6494 Sgr 17 56.9 -19 01 5.5 Op. Cl.

M24 NGC 6603 Sgr 18 16.4 -18 29 4.5 Op. Cl.

M25 IC 4725 Sgr 18 31.7 -19 15 4.6 Op. Cl.

M26 NGC 6694 Sct 18 45.2 -9 24 8.0 Op. Cl.

M27 NGC 6853 Vul 19 59.6 22 43 8.1 P. Neb. Dumbbell Nebula

M28 NGC 6626 Sgr 18 24.6 -24 52 6.9 Gl. Cl.

M29 NGC 6913 Cyg 20 23.0 38 32 6.6 Op. Cl.

M30 NGC 7099 Cap 21 40.4 -23 11 7.5 Gl. Cl.

M31 NGC 224 And 0 42.7 41 16 3.4 Sp. Gx. Andromeda Galaxy

M32 NGC 221 And 0 42.7 40 52 8.2 El. Gx.

M33 NGC 598 Tri 1 33.8 30 39 5.7 Sp. Gx. Pinwheel Galaxy

M34 NGC 1039 Per 2 42.0 42 47 5.2 Op. Cl.

M35 NGC 2168 Gem 6 08.8 24 20 5.1 Op. Cl.

The Messier Catalog • 71

M# NGC# Const. R.A. DEC Mag Type Proper Name

H M S ° ‘

M36 NGC 1960 Aur 5 36.3 34 08 6.0 Op. Cl.

M37 NGC 2099 Aur 5 52.0 32 33 5.6 Op. Cl.

M38 NGC 1912 Aur 5 28.7 35 50 6.4 Op. Cl.

M39 NGC 7092 Cyg 21 32.3 48 26 4.6 Op. Cl.

M40 UMa 12 22.2 58 05 8.0 dbl

M41 NGC 2287 CMa 6 47.0 -20 44 4.5 Op. Cl.

M42 NGC 1976 Ori 5 35.3 -5 27 4.0 D. Neb. Great Orion Nebula

M43 NGC 1982 Ori 5 35.5 -5 16 9.0 D. Neb.

M44 NGC 2632 Cnc 8 40.0 19 59 3.1 Op. Cl. Beehive Cluster

M45 Tau 3 47.5 24 07 1.2 Op. Cl. Pleiades

M46 NGC 2437 Pup 7 41.8 -14 49 6.1 Op. Cl.

M47 NGC 2422 Pup 7 36.6 -14 30 4.4 Op. Cl.

M48 NGC 2548 Hya 8 13.8 -5 48 5.8 Op. Cl.

M49 NGC 4472 Vir 12 29.8 8 00 8.4 El. Gx.

M50 NGC 2323 Mon 7 03.0 -8 20 5.9 Op. Cl.

M51 NGC 5194-5 CVn 13 29.9 47 12 8.1 Sp. Gx. Whirlpool Galaxy

M52 NGC 7654 Cas 23 24.2 61 35 6.9 Op. Gx.

M53 NGC 5024 Com 13 12.9 18 10 7.7 Gl. Cl.

M54 NGC 6715 Sgr 18 55.1 -30 29 7.7 Gl. Cl.

M55 NGC 6809 Sgr 19 40 .0 -30 58 7.0 Gl. Cl.

M56 NGC 6779 Lyr 19 16.6 30 11 8.2 Gl. Cl.

M57 NGC 6720 Lyr 18 53.6 33 02 9.0 P. Neb. Ring Nebula

M58 NGC 4579 Vir 12 37.7 11 49 9.8 Sp. Gx.

M59 NGC 4621 Vir 12 42.0 11 39 9.8 El. Gx.

M60 NGC 4649 Vir 12 43.7 11 33 8.8 El. Gx.

M61 NGC 4303 Vir 12 21.9 4 28 9.7 Sp. Gx.

M62 NGC 6266 Oph 17 01.2 -30 07 6.6 Gl. Cl.

M63 NGC 5055 CVn 13 15.8 42 02 8.6 Sp. Gx. Sunflower Galaxy

M64 NGC 4826 Com 12 56.7 21 41 8.5 Sp. Gx. Black Eye Galaxy

M65 NGC 3623 Leo 11 18.9 13 05 9.3 Sp. Gx. Leo’s Triplet

M66 NGC 3627 Leo 11 20.3 12 59 9.0 Sp. Gx. Leo’s Triplet

M67 NGC 2682 Cnc 8 50.3 11 49 6.9 Op. Cl.

M68 NGC 4590 Hya 12 39.5 -26 45 8.2 Gl. Cl.

M69 NGC 6637 Sgr 18 31.4 -32 21 7.7 Gl. Cl.

M70 NGC 6681 Sgr 18 43.2 -32 18 8.1 Gl. Cl.

M71 NGC 6838 Sge 19 53.7 18 47 8.3 Gl. Cl.

M72 NGC 6981 Aqr 20 53.5 -12 32 9.4 Gl. Cl.

M73 NGC 6994 Aqr 20 58.0 -12 38 ast

M74 NGC 628 Psc 1 36.7 15 47 9.2 S

M75 NGC 6864 Sgr 20 06.1 -21 55 8.6 Gl Cl.

M76 NGC 650-1 Per 1 42.2 51 34 11.5 P. Neb. Cork Nebula

M77 NGC 1068 Cet 2 42.7 0 01 8.8 Sp. Gx.

M78 NGC 2068 Ori 5 46.7 0 03 8.0 D. Neb.

M79 NGC 1904 Lep 5 24.2 -24 33 8.0 Gl. Cl.

M80 NGC 6093 Sco 16 17.0 -22 59 7.2 Gl. Cl.

72 • The Messier Catalog

M# NGC# Const. R.A. DEC Mag Type Proper Name

H M S ° ‘

M81 NGC 3031 UMa 9 55.8 69 04 6.8 Sp. Gx. Bodes Nebula

M82 NGC 3034 UMa 9 56.2 69 41 8.4 Ir. Gx.

M83 NGC 5236 Hya 13 37.7 -29 52 7.6 Sp. Gx.

M84 NGC 4374 Vir 12 25.1 12 53 9.3 El. Gx.

M85 NGC 4382 Com 12 25.4 18 11 9.2 El. Gx.

M86 NGC 4406 Vir 12 26.2 12 57 9.2 El. Gx.

M87 NGC 4486 Vir 12 30.8 12 24 8.6 El. Gx. Virgo A

M88 NGC 4501 Com 12 32.0 14 25 9.5 Sp. Gx.

M89 NGC 4552 Vir 12 35.7 12 33 9.8 El. Gx.

M90 NGC 4569 Vir 12 36.8 13 10 9.5 Sp. Gx.

M91 NGC 4548 Com 12 35.4 14 30 10.2 Sp. Gx.

M92 NGC 6341 Her 17 17.1 43 08 6.5 Gl. Cl.

M93 NGC 2447 Pup 7 44.6 -23 52 6.2 Op. Cl.

M94 NGC 4736 CVn 12 50.9 41 07 8.1 Sp. Gx.

M95 NGC 3351 Leo 10 44.0 11 42 9.7 Sp. Gx.

M96 NGC 3368 Leo 10 46.8 11 49 9.2 Sp. Gx.

M97 NGC 3587 UMa 11 14.9 55 01 11.2 P. Neb. Owl Nebula

M98 NGC 4192 Com 12 13.8 14 54 10.1 Sp. Gx.

M99 NGC 4254 Com 12 18.8 14 25 9.8 Sp. Gx. Pin Wheel Nebula

M100 NGC 4321 Com 12 22.9 15 49 9.4 Sp. Gx.

M101 NGC 5457 UMa 14 03.2 54 21 7.7 Sp. Gx.

M102 NGC 5457 UMa 14 03.2 54 21 7.7 dup

M103 NGC 581 Cas 1 33.1 60 42 7.4 Op. Cl.

M104 NGC 4594 Vir 12 40.0 -11 37 8.3 Sp. Gx. Sombrero Galaxy

M105 NGC 3379 Leo 10 47.9 12 35 9.3 El. Gx..

M106 NGC 4258 CVn 12 19.0 47 18 8.3 Sp. Gx.

M107 NGC 6171 Oph 16 32.5 -13 03 8.1 Gl. Cl.

M108 NGC 3556 UMa 11 11.6 55 40 10.0 Sp. Gx.

M109 NGC 3992 UMa 11 57.7 53 23 9.8 Sp. Gx.

M110 NGC 205 And 0 40.3 41 41 8.0 El. Gx.

Object Abbreviations:

• Sp. Gx. ................Spiral Galaxy

• El. Gx. ................. Elliptical Galaxy

• Ir. Gx.................... Irregular Galaxy

• Op. Cl. ................. Open Cluster

• Gl. Cl. .................. Globular Cluster

• D. Neb.................. Diffuse Nebula

• P. Neb.................. Planetary Nebula

NOTE: All coordinates for the objects in the Messier catalog are listed in epoch 2000.00.

List of Bright Stars • 73

LIST OF BRIGHT STARS

The following is a list of bright stars that can be used to align the R.A. setting circle. All coordinates are in

epoch 2000.0.

Epoch 2000.0

Star Name Constellation R.A. DEC Magnitude

H M S ° ‘ “

Sirius CMa 06 45 09 -16 42 58 -1.47

Canopus Car 06 23 57 -52 41 44 -0.72

Arcturus Boo 14 15 40 +19 10 57 -0.72

Rigel Kent. Cen 14 39 37 -60 50 02 +0.01

Vega Lyr 18 36 56 +38 47 01 +0.04

Capella Aur 05 16 41 +45 59 53 +0.05

Rigel Ori 05 14 32 -08 12 06 +0.14

Procyon CMi 07 38 18 +05 13 30 +0.37

Betelgeuse Ori 05 55 10 +07 24 26 +0.41

Achernar Eri 01 37 43 -57 14 12 +0.60

Hadar Cen 14 03 49 -60 22 22 +0.63

Altair Aqi 19 50 47 +08 52 06 +0.77

Aldebaran Tau 04 35 55 +16 30 33 +0.86

Spica Vir 13 25 12 -11 09 41 +0.91

Antares Sco 16 29 24 -26 25 55 +0.92

Fomalhaut PsA 22 57 39 -29 37 20 +1.15

Pollux Gem 07 45 19 +28 01 34 +1.16

Deneb Cyg 20 41 26 +45 16 49 +1.28

Beta Crucis Cru 12 47 43 -59 41 19 +1.28

Regulus Leo 10 08 22 +11 58 02 +1.36

FOR FURTHER READING

The following is a list of astronomy books that will further enhance your understanding of the night sky. The

books are broken down by classification for easy reference.

Astronomy Texts

Astronomy Now ......................................................................................... Pasachoff & Kutner

Cambridge Atlas Of Astronomy ................................................................. Audouze & Israel

McGraw-Hill Encyclopedia Of Astronomy .................................................. Parker

Astronomy-The Evolving Universe ............................................................... Zeilik

Atlases

Atlas Of Deep Sky Splendors .................................................................... Vehrenberg

Sky Atlas 2000.0 ....................................................................................... Tirion

Sky Catalog 2000.0 Vol 1 & 2.................................................................... Hirshfeld & Sinnott

Uranometria Vol. 1 & 2 .............................................................................. Tirion, Rappaport, Lovi

Magnitude 6 Star Atlas .............................................................................. Dickinson, Costanzo, Chaple

NGC 2000.0............................................................................................... Sinnott

General Observational Astronomy

The Cambridge Astronomy Guide .............................................................. Liller & Mayer

A Complete Manual Of Amateur Astronomy .............................................. Sherrod

The Guide To Amateur Astronomy ............................................................. Newton & Teece

Visual Observation

Observational Astronomy For Amateurs ..................................................... Sidgwick

Astronomical Calendar ............................................................................... Ottewell

Burnham’s Celestial Handbook Vols. 1, 2 & 3............................................ Burnham

The Planet Jupiter ...................................................................................... Peek

Field Guide To The Stars & Planets ........................................................... Menzel & Pasachoff

Observe Comets ........................................................................................ Edberg & Levy

Astrophotography

Skyshooting .............................................................................................. Mayall & Mayall

Astrophotography A Step-by-Step Approach .............................................. Little

Astrophotography For The Amateur ........................................................... Covington

Astrophotography ...................................................................................... Gordon

Astrophotography II .................................................................................... Martinez

A Manual Of Celestial Photography ........................................................... King

Manual Of Advanced Celestial Photography ............................................... Wallis & Provin

Colours Of The Stars ................................................................................. Malin & Muirden

CELESTRON ONE YEAR WARRANTY

A. Celestron International (CI) warrants this telescope to be free from defects in materials and workmanship for one year. CI will repair or

replace such product or part thereof which, upon inspection by CI, is found to be defective in materials or workmanship. As a condition

to the obligation of CI to repair or replace such product, the product must be returned to CI together with proof-of-purchase satisfactory

to CI.

B. The Proper Return Authorization Number must be obtained from CI in advance of return. Call Celestron at (310) 328-9560 to receive the

number to be displayed on the outside of your shipping container.

All returns must be accompanied by a written statement setting forth the name, address, and daytime telephone number of the owner,

together with a brief description of any claimed defects. Parts or product for which replacement is made shall become the property of CI.

The customer shall be responsible for all costs of transportation and insurance, both to and from the factory of CI, and shall

be required to prepay such costs.

CI shall use reasonable efforts to repair or replace any telescope covered by this warranty within thirty days of receipt. In the event repair

or replacement shall require more than thirty days, CI shall notify the customer accordingly. CI reserves the right to replace any product

which has been discontinued from its product line with a new product of comparable value and function.

This warranty shall be void and of no force of effect in the event a covered product has been modified in design or function,

or subjected to abuse, misuse, mishandling or unauthorized repair. Further, product malfunction or deterioration due to

normal wear is not covered by this warranty.

CI DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WHETHER OF MERCHANTABILITY OF FITNESS FOR A PARTICU-

LAR USE, EXCEPT AS EXPRESSLY SET FORTH HEREIN.

THE SOLE OBLIGATION OF CI UNDER THIS LIMITED WARRANTY SHALL BE TO REPAIR OR REPLACE THE COVERED

PRODUCT, IN ACCORDANCE WITH THE TERMS SET FORTH HEREIN. CI EXPRESSLY DISCLAIMS ANY LOST PROFITS,

GENERAL, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES WHICH MAY RESULT FROM BREACH OF ANY WAR-

RANTY, OR ARISING OUT OF THE USE OR INABILITY TO USE ANY CI PRODUCT. ANY WARRANTIES WHICH ARE IMPLIED

AND WHICH CANNOT BE DISCLAIMED SHALL BE LIMITED IN DURATION TO A TERM OF ONE YEAR FROM THE DATE OF

ORIGINAL RETAIL PURCHASE.

Some states do not allow the exclusion or limitation of incidental or consequential damages or limitation on how long an implied warranty

lasts, so the above limitations and exclusions may not apply to you.

This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.

CI reserves the right to modify or discontinue, without prior notice to you, any model or style telescope.

If warranty problems arise, or if you need assistance in using your telescope contact:

Celestron International

Customer Service Department

2835 Columbia Street

Torrance, CA 90503

Tel. (310) 328-9560

Fax. (310) 212-5835

Monday-Friday 8AM-4PM PST

This warranty supersedes all other product warranties.

0698

NOTE: This warranty is valid to U.S.A. and Canadian customers who have purchased this product from an Authorized CI

Dealer in the U.S.A. or Canada. Warranty outside the U.S.A. and Canada is valid only to customers who purchased

from a CI International Distributor or Authorized CI Dealer in the specific country and please contact them for

any warranty service.

Celestron International

2835 Columbia Street

Torrance, CA 90503

Tel: 310-328-9560

Fax: 310-212-5835

Web site: http://www.celestron.com

(Products or instructions may change

without notice or obligation).

Item #11055-INST

07-98

Price $10.00

Celestron 11055 Users Manual

11055 Ci700a

11065 55351133-35a9-4256-bbe5-0ab873b6c579

91525 to the manual 55351133-35a9-4256-bbe5-0ab873b6c579

Navigation menu

Versions of this User Manual:

Views

Navigation