Celestron C10-NGT User Manual

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INTRODUCTION....................................................................................................................................................................................................4

Warning ................................................................................................................................................................................................................ 4

ASSEMBLY ............................................................................................................................................................................................................. 7

Setting up the Tripod............................................................................................................................................................................................. 7

Attaching the Equatorial Mount............................................................................................................................................................................ 7

Attaching the Center Leg Brace ............................................................................................................................................................................8

Installing the Counterweight Bar ..........................................................................................................................................................................8

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

Attaching the Hand Control Holder ......................................................................................................................................................................9

Attaching the Slow Motion Knobs........................................................................................................................................................................9

Attaching the Telescope Tube to the Mount........................................................................................................................................................10

Installing the Finderscope...................................................................................................................................................................................11

Installing the Eyepieces.......................................................................................................................................................................................11

Balancing the Tube in R.A.................................................................................................................................................................................. 12

Adjusting the Mount...........................................................................................................................................................................................13

Adjusting the Mount in Altitude........................................................................................................................................................13

Adjusting the Mount in Azimuth....................................................................................................................................................... 14

Attaching the Declination Cables (For GT Models Only) ...................................................................................................................................14

Powering the Telescope ...................................................................................................................................................................................... 14

HAND CONTROL................................................................................................................................................................................................. 15

Hand Control Operation...................................................................................................................................................................................... 16

Alignment Procedures......................................................................................................................................................................................... 17

Startup Procedure................................................................................................................................................................................................ 17

Auto Align ..........................................................................................................................................................................................................18

Auto Three-Star Align ........................................................................................................................................................................................18

Quick-Align........................................................................................................................................................................................................19

Last Alignment ...................................................................................................................................................................................................19

Re-Alignment......................................................................................................................................................................................................19

Object Catalog ....................................................................................................................................................................................................20

Selecting an Object ........................................................................................................................................................................... 20

Slewing to an Object .........................................................................................................................................................................20

Finding Planets..................................................................................................................................................................................20

Tour Mode ........................................................................................................................................................................................ 21

Constellation Tour............................................................................................................................................................................. 21

Direction Buttons .............................................................................................................................................................................. 21

Rate Button .......................................................................................................................................................................................21

Setup Procedures................................................................................................................................................................................................. 22

Tracking Mode..........................................................................................................................................................................................22

Tracking Rate............................................................................................................................................................................................22

Date/Time ................................................................................................................................................................................................. 22

User Defined Objects ................................................................................................................................................................................22

Get RA/DEC.............................................................................................................................................................................................23

Goto R.A/Dec............................................................................................................................................................................................23

Identify......................................................................................................................................................................................................23

Precise GoTo.....................................................................................................................................................................................24

Scope Setup Features ........................................................................................................................................................................24

Setup Time-Site.........................................................................................................................................................................................24

Anti-backlash............................................................................................................................................................................................ 24

Filter Limits ..............................................................................................................................................................................................24

Direction Buttons ...................................................................................................................................................................................... 25

Goto Approach.......................................................................................................................................................................................... 25

Autoguide Rates........................................................................................................................................................................................25

Azimuth Limits......................................................................................................................................................................................... 25

East/West Filtering.................................................................................................................................................................................... 26

Utility Features ...................................................................................................................................................................................................26

Calibrate Goto........................................................................................................................................................................................... 26

Home Position...........................................................................................................................................................................................26

Polar Align ................................................................................................................................................................................................26

Light Control.............................................................................................................................................................................................27

Factory Settings......................................................................................................................................................................................... 27

Version...................................................................................................................................................................................................... 27

Get Alt-Az.................................................................................................................................................................................................27

Goto Alt-Az ..............................................................................................................................................................................................27

Hibernate...................................................................................................................................................................................................27

Turn On/Off GPS ...................................................................................................................................................................................... 27

TELESCOPE BASICS ..........................................................................................................................................................................................29

Image Orientation ...............................................................................................................................................................................................29

Focusing..............................................................................................................................................................................................................30

Aligning the Finderscope ....................................................................................................................................................................................30

Calculating Magnification...................................................................................................................................................................................30

Determining Field of View ................................................................................................................................................................................. 31

General Observing Hints..................................................................................................................................................................................... 31

ASTRONOMY BASICS........................................................................................................................................................................................ 32

The Celestial Coordinate System ........................................................................................................................................................................32

Motion of the Stars.............................................................................................................................................................................................. 33

Finding the North Celestial Pole ......................................................................................................................................................................... 35

Declination Drift Method of Polar Alignment..................................................................................................................................................... 36

CELESTIAL OBSERVING..................................................................................................................................................................................37

Observing the Moon............................................................................................................................................................................................37

Lunar Observing Hints........................................................................................................................................................................................ 37

Observing the Planets..........................................................................................................................................................................................37

Observing the Sun............................................................................................................................................................................................... 37

Solar Observing Hints......................................................................................................................................................................................... 38

Observing Deep Sky Objects .............................................................................................................................................................................. 38

Seeing Conditions ...............................................................................................................................................................................................38

Transparency.......................................................................................................................................................................................................38

Sky Illumination..................................................................................................................................................................................................38

Seeing ................................................................................................................................................................................................................. 38

ASTROPHOTOGRAPHY .................................................................................................................................................................................... 40

Piggyback ...........................................................................................................................................................................................................40

Short Exposure Prime Focus Photography.......................................................................................................................................................... 41

Terrestrial Photography.......................................................................................................................................................................................42

Metering..............................................................................................................................................................................................................42

Reducing Vibration.............................................................................................................................................................................................42

Auto Guiding ......................................................................................................................................................................................................43

TELESCOPE MAINTENANCE .......................................................................................................................................................................... 44

Care and Cleaning of the Optics.......................................................................................................................................................................... 44

Collimation.........................................................................................................................................................................................................44

OPTIONAL ACCESSORIES.............................................................................................................................................................................. 48

APPENDIX A – TECHNICAL SPECIFICATIONS.........................................................................................................................................51

APPENDIX B – GLOSSARY OF TERMS.........................................................................................................................................................52

APPENDIX C – LONGITUDES AND LATITUDES..........................................................................................................................................55

APPENDIX D – RS-232 CONNECTION............................................................................................................................................................. 60

APPENDIX E – TIME ZONE MAP.....................................................................................................................................................................62

SKY MAPS............................................................................................................................................................................................................. 64

Congratulations on your purchase of the Celestron Advanced Series telescope (AST)! The Advanced Series of telescopes come in standard (non-computerized) and computerized GT models. The Advanced Series is made of the highest quality materials to ensure stability and durability. All this adds up to a telescope that gives you a lifetime of pleasure with a minimal amount of maintenance. Furthermore, your Celestron telescope is versatile — it will grow as your interest grows.

The Advanced GT Series ushers in the next generation of computer automated telescopes. The Celestron Advanced GT series continues in this proud tradition combining large aperture optics with the sophistication and ease of use of our computerized GoTo mount.

If you are new to astronomy, you may wish to start off by using the built-in Sky Tour feature, which commands the telescopes to find the most interesting objects in the sky and automatically slews to each one. Or if you are an experienced amateur, you will appreciate the comprehensive database of over 40,000 objects, including customized lists of all the best deep-sky objects, bright double stars and variable stars. No matter at what level you are starting out, the Advanced Series telescopes will unfold for you and your friends all the wonders of the Universe.

Some of the many standard features of the Advanced GT include:

• Fully enclosed optical encoders for position location.

• Ergonomically designed mount that disassembles into compact and portable pieces.

• Database filter limits for creating custom object lists.

• Storage for programmable user defined objects; and

Many other high performance features!

The AST’s deluxe features combine with Celestron’s legendary optical systems to give amateur astronomers the most sophisticated and easy to use telescopes available on the market today.

Take time to read through this manual before embarking on your journey through the Universe. It may take a few observing sessions to become familiar with your telescope, so you should keep this manual handy until you have fully mastered your telescope’s operation. The Advanced GT hand control has built-in instructions to guide you through all the alignment procedures needed to have the telescope up and running in minutes. Use this manual in conjunction with the on-screen instructions provided by the hand control. The manual gives detailed information regarding each step as well as needed reference material and helpful hints guaranteed to make your observing experience as simple and pleasurable as possible.

Your telescope is designed to give you years of fun and rewarding observations. However, there are a few things to consider before using your telescope that will ensure your safety and protect your equipment.

Warning

Y Never look directly at the sun with the naked eye or with a telescope (unless you have the proper

solar filter). Permanent and irreversible eye damage may result.

Y Never use your telescope to project an image of the sun onto any surface. Internal heat build-up can damage the telescope

and any accessories attached to it.

Y 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 children are present or adults who may not be familiar with the correct operating procedures of your telescope

Fig 1-1 - The Advanced Series Newtonian

(C8-N Shown)

1. Finderscope 7. 2" Steel Tripod

2. Finderscope Bracket 8. Center Leg Brace / Accessory Tray

3. Eyepiece 9. Counterweights

4. Focuser 10. Counterweight Bar

5. Tube Rings 11. Dovetail Slide Bar

6. Latitude Adjustment Lever 12. Optical Tube

Fig 1-2 - The Advanced Series GT Newtonian

(C8-NGT Shown)

1. Finderscope 8. Center Leg Brace / Accessory Tray

2. Finderscope Bracket 9. Counterweights

3. Eyepiece 10. Counterweight Bar

4. Focuser 11. Dovetail Slide Bar

5. Tube Rings 12. Optical Tube

6. Latitude Adjustment Lever 13. Hand Control

7. 2" Steel Tripod 14. R.A. Motor Drive / Control Panel CONTROL PANEL 15. Declination Motor Drive

A Hand Control Port B DEC Motor Port D 12v Output Jack C Autoguide Port E ON/OFF Switch

This section covers the assembly instructions for your Celestron Advanced Series Telescope (AST). Your AST telescope should be set up indoor the first time so that it is easy to identify the various parts and familiarize yourself with the correct assembly procedure before attempting it outdoor.

Diameter

Focal Length

Eyepiece

Finderscope

Mount

Tripod

Software

Counterweight

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31061 / 31062 11047 / 11048

C8-N C10-N

200mm (8.0") reflector 254mm (10") reflector

1000mm F/5 Parabola 1200mm F/4.7 Parabola

20mm - 1.25" (50x) 20mm – 1.25" (60x)

9x50 9x50

CG-5 Equatorial CG-5 Equatorial

2" Stainless Steel 2" Stainless Steel

The Sky L1 The Sky L1

2-11lb 3-11lb

The CG-5 tripod comes with an all metal center leg brace / accessory tray to give rock solid support to the mount. The tripod comes fully assembled with a metal plate, called the tripod head, that holds the legs together at the top. In addition, there is a central rod that extends down from the tripod head that attaches the equatorial mount to the tripod. To set up the tripod:

1. Stand the tripod upright and pull the tripod legs apart until each leg is fully extended. The tripod will now stand by itself. Once the tripod is set up, you can adjust the height at which it stands.

2. Loosen the lever on the leg clamp so that the tripod leg can be adjusted.

3. Slide the center portion of the tripod leg away from the tripod

Equatorial

Moun

head until it is at the desired height.

4. Tighten the levers on each leg clamp to hold the legs in place.

Azimuth Alignment Screws

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Tripod

Head

Alignment Peg

The equatorial mount allows you to tilt the telescope’s axis of rotation so that you can track the stars as they move across the sky. The CG-5 mount is a German equatorial mount that

Mounting Knob

attaches to the tripod head. On one side of the tripod head there is a metal alignment peg for aligning the mount. This side of the tripod will face north when setting up for an astronomical observing session. To attach the equatorial head:

Figure 2-3

1. Locate the azimuth adjustment screws on the equatorial mount.

2. Retract the screws so they no longer extend into the azimuth housing on the mount. Do NOT remove the screws since they are needed later for polar alignment.

3. Hold the equatorial mount over the tripod head so that the azimuth housing is above the metal peg.

4. Place the equatorial mount on the tripod head so that the two are flush.

5. Tighten the knob (attached to the central rod) on the underside of the tripod head to hold the equatorial mount firmly in place.

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1. Slide the accessory tray over the central rod so that each arm of the tray is pushing against the inside of the

tripod legs.

2. Thread the accessory tray knob on to the central rod and tighten.

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To properly balance the telescope, the mount comes with a counterweight bar and at least one counterweight (depending on model). To install the counterweight bar:

1. Locate the opening in the equatorial mount on the DEC axis

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

3. Tighten the counterweight bar lock nut fully for added support (see fig 2-5).

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

Since the fully assembled telescope can be quite heavy, position the mount so that the polar axis is pointing towards north before the tube assembly and counterweights are attached. This will make the polar alignment procedure much easier.

Mounting Knob

Figure 2-3

Central Rod

Accessory Tray

Accessory Tray Knob

Figure 2-4

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Depending on which AST telescope you have, you will receive either two or three counterweights. To install the counterweight(s):

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

2. Remove the counterweight safety screw on the end of the counterweight bar (i.e., opposite the end that attaches to the mount).

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

4. Slide the counterweight onto the shaft (see Figure 2-5).

5. Tighten the locking screw on the side of the weight to hold the counterweight in place.

6. Replace the counterweight safety screw.

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The Advanced GT telescope models come with a hand control holder to place the computerized hand control. The hand control holder comes in two pieces: the leg clamp that snaps around the tripod leg and the holder which attaches to the leg clamp. To attach the hand control holder:

1. Place the leg clamp up against one of the tripod legs and press firmly until the clamp wraps around the leg.

2. Slide the back of the hand control holder downward into the channel on the front of the legs clamp (see Fig 2-6) until it snaps into place.

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The Advanced Series (non-GT models) comes with two slow motion control knobs that allows you to make fine pointing adjustments to the telescope in both R.A. and Declination. To install the knobs:

1. Locate the hard plastic shell under the R.A. shafts.

2. Remove either of the two oval tabs by pulling tightly.

3. Line up the flat area on the inner portion of the R.A. slow motion knob with the flat area on the R.A. shaft (see Fig 2-7).

4. Slide the R.A. slow motion knob onto the R.A. shaft.

Counterweight Bar

Locking Nu

Counterweight

Locking Screw

Counterweigh

Safety Screw

Bar

Figure 2-5

)

Figure 2-6

Hand Control Holder

Leg Clamp

Figure 2-7

The knob is a tension fit, so sliding it on holds it in place. As mentioned above, there are two R.A. shafts, one on either side of the mount. It makes no difference which shaft you use since both work the same. Use whichever one you find more convenient. If, after a few observing sessions, you find the R.A. slow motion knob is more accessible from the other side, pull firmly to remove the knob, then install it on the opposite side.

5. The DEC slow motion knob attaches in the same manner as the R.A. knob. The shaft that the DEC slow motion knob fits over is toward the top of the mount, just below the telescope mounting platform. Once again, you have two shafts to choose from. Use the shaft that is pointing toward the ground. This makes it easy to reach while looking through the telescope, something which is quite important when you are observing.

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

Advanced

GT Users!

bottom of the telescope tube. 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

Declination Index Marks

suddenly while attaching the telescope. To mount the telescope

tube:

In order for the GT computerized mount to function properly, before installing the optical tube, the mounting platform must be positioned so that the Declination Index Marks are aligned (see Fig 2-8).

1 Locate the mounting bracket from the box containing the equatorial mount head.

Figure 2-8

2 Attach the mounting bracket to the tube rings so that the tapered (narrow) end is against the bottom of the tube rings.

3 Loosen the hand knob on the side of the CG-5 mount.

4 Slide the mounting bracket that is attached to the bottom of the tube rings into the recess on the top of the mounting platform (see figure 2-9).

5 Tighten the telescope mounting screw on the CG-5 mount to hold the telescope in place.

6 Hand tighten the mounting platform safety screw until the tip touches the side of the mounting bracket.

NOTE: Never loosen any of the knobs on

the telescope tube or mount. Also, be sure that the open end of the telescope is pointing away from the ground at all times.

Figure 2-9

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To install the finderscope onto the telescope you must first mount the finderscope through the finder bracket and then attach it to the telescope. Toward the front of the telescope tube, near the focusing assembly, there is a small bracket with a set screw in it. This is where the finderscope bracket will be mounted. To install the finderscope:

1. Slide the rubber O-ring over the eyepiece end of the finderscope and roll it 2/3 of the way up the

finderscope.

2. Insert the eyepiece end of the finderscope through the

bracket until the O-ring presses tightly between the finder and the inside of the bracket.

3. Tighten the adjustment screws until they make contact with

the finderscope body.

4. Locate the mounting bracket near the front (open) end of the

telescope.

5. Loosen the set screw on the mounting bracket on the telescope.

Figure 2-10

6. Slide the finder bracket (attached to the finderscope) into the mounting bracket on the telescope.

7. The finderscope bracket will slide in from the back. The finderscope should be oriented so that the

objective lens is toward the front (open) end of the telescope.

8. Tighten the set screw on the mounting bracket to hold the finderscope in place.

For information on aligning your finderscope, see Telescope Basics section of this manual.

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The eyepiece, or ocular as it is also called, is an optical element that magnifies the image focused by the telescope. Without the eyepiece it would be impossible to use the telescope visually. The eyepiece fits directly into the eyepiece holder. To attach an ocular:

1. Loosen the set screw on the eyepiece holder so that it does not obstruct the inner diameter of the eyepiece holder.

2. Slide the chrome portion of the eyepiece into the eyepiece holder.

3. Tighten the set screw to hold the eyepiece in place.

To remove the eyepiece, loosen the set screw on the eyepiece holder and slide

Figure 2-11

the eyepiece out. You can replace it with another ocular.

Eyepieces are commonly referred to by focal length which 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 magnification. Generally, you will use low-tomoderate power when viewing.

Your telescope can use eyepieces with both a 1-1/4" barrel diameter and 2" barrel diameter. To use a 2" barrel eyepiece, the 1 1/4" eyepiece adapter must first be removed and replaced with the included 2" eyepiece adapter. To do this, simply loosen the two chrome thumbscrews located around the focuser barrel (see figure 2-12) and remove the 1 1/4" adapter. Once removed, a 2" eyepiece adapter can be inserted directly into the focuser barrel and secured with the two thumb screws.

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To eliminate undue stress on the mount, the telescope should be properly balanced around the polar axis. In addition, proper balancing is crucial for accurate tracking if using an optional motor drive. To balance the mount:

1. Release the R.A. Clamp (figure 2-16) and position the telescope off to one side of the mount (make sure that the mounting bracket screw is tight). The counterweight bar will extend horizontally on the opposite side of the mount (see figure 2-13).

2. Release the telescope — GRADUALLY — to see which way the telescope “rolls.”

3. Loosen the set screw on the counterweight.

4. Move the counterweight to a point where it balances the telescope (i.e., it remains stationary when the R.A. clamp is released).

5. Tighten the set screw to hold the counterweight(s) in place.

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 Telescope in DEC

The telescope should also be balanced on the declination axis to prevent any sudden motions when the DEC clamp (figure 2-16) is released. To balance the telescope in DEC:

1. Release the R.A. clamp 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 telescope in R.A.).

2. Lock the R.A. clamp to hold the telescope in place.

3. Release the DEC clamp and rotate the telescope until the tube is parallel to the ground (see figure 2-14).

4. Release the tube — GRADUALLY — to see which way it rotates around the declination axis. DO NOT LET GO

OF THE TELESCOPE TUBE COMPLETELY!

2" Eyepiece Adapter

Figure 2-12

5. Loosen the screws that hold the telescope tube inside the mounting rings and slide the telescope either forwards or backwards until it remains stationary when the DEC clamp is released.

6. Tighten the tube ring screws firmly to hold the telescope in place.

Like the 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.

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In order for a motor 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 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.”

Adjusting the Mount in Altitude

• To increase the latitude of the polar axis, tighten the rear latitude adjustment screw and loosen the front screw (if necessary).

• To decrease the latitude of the polar axis, tighten the front (under the counterweight bar) latitude adjustment screw and loosen the rear screw (if necessary).

The latitude adjustment on the CG-5 mount has a range from approximately 30° going up to 60°.

It is best to always make final adjustments in altitude by moving the mount against gravity (i.e. using the rear latitude adjustment screw to raise the mount). To do this you should loosen both latitude adjustment screws and manually push the front of the mount down as far as it will go. Then tighten the rear adjustment screw to raise the mount to the desired latitude.

Figure 2-13

Figure 2-14

Rear Latitude Adjustment Screw

Front Latitude Adjustment Screw

Azimuth Adjustment Knobs

Figure 2-15

For Advanced GT users, it may be helpful to remove the front latitude adjustment screw completely. This will allow the mount to reach lower latitudes without the screw coming into contact with the R.A. motor assembly. To remove the latitude screw, first use the rear screw to raise the mount head all the way up. Then remove the front latitude screw completely. Now you should be able to manually move the mount head all the way to its lowest latitude. Now, using only the rear screw, raise the mount to your desired latitude.

Adjusting the Mount in Azimuth

For rough adjustments in azimuth, simply pick up the telescope and tripod and move it. For fine adjustments in azimuth:

1. Turn the azimuth adjustment knobs located on either side of the azimuth housing (see Fig 2-15). While standing behind the telescope, the knobs are on the front of the mount.

• Turning the right adjustment knob clockwise moves the mount toward the right.

• Turning the left adjustment knob clockwise moves the mount to the left.

Both screws push off of the peg on the tripod head, which means you may have to loosen one screw while tightening the other. The screw that holds the equatorial mount to the tripod may have to be loosened slightly.

Keep in mind that adjusting the mount is done during the polar alignment process only. Once polar aligned, the mount must NOT be moved. Pointing the telescope is done by moving the mount in right ascension and declination, as described earlier in this manual.

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The Advanced Series mount comes with a declination cable that connects from the R.A. motor drive electronic panel to the Dec motor drive. To attach the motor cable:

Locate the Declination cable and plug one end of the cable into the port on the electronics panel labeled DEC Port and plug the other end of the cable into the port located on the declination motor drive (see Fig 2-16).

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The Advanced GT can be powered by the supplied car battery adapter or optional 12v AC adapter. Use only adapters supplied by Celestron. Using any other adapter may damage the electronics or cause the telescope not to operate properly, and will void your manufacturer's warranty.

1. To power the telescope with the car battery adapter (or 12v AC adapter), simply plug the round post into the 12v outlet on the

electronic panel and plug the other end into your cars cigarette lighter outlet or portable power supply (see Optional Accessories). Note: to prevent the power cord from being accidentally pulled out, wrap the power cord around the strain relief located below the power switch.

2. Turn on the power to the telescope by flipping the switch, located on the electronics panel, to the "On" position.

R.A. Locking

Clamp

Figure 2-16

DEC Locking Clamp

Declination Cable Input Port

Declination Cable Output Port

12v Power Input

On/Off Switch

Figure 2-16

The Advanced Series GT, computerized version of each telescope has a hand controller designed to give you instant access to all the functions that your telescope has to offer. With automatic slewing to over 40,000 objects, and common sense menu descriptions, even a beginner can master its variety of features in just a few observing sessions. Below is a brief description of the individual components of the computerized hand controller:

1. Liquid Crystal Display (LCD) Window: Has a dual-line, 16 character display screen that is backlit for comfortable viewing of telescope information and scrolling text.

2. Align: Instructs the telescope to use a selected star or object as an alignment position.

3. Direction Keys: Allows complete control of the telescope in any direction. Use the direction keys to move the telescope to the initial alignment stars or for centering objects in the eyepiece.

Figure 3-1

The Advanced GT Hand Control

4. Catalog Keys: The Advanced Series has keys on the hand control to allow direct access to each of the catalogs in its database. The hand control contains the following catalogs in its database:

Messier – Complete list of all Messier objects. NGC – Complete list of all the deep-sky objects in the Revised New General Catalog. Caldwell – A combination of the best NGC and IC objects. Planets - All 8 planets in our Solar System plus the Moon. Stars – A compiled list of the brightest stars from the SAO catalog. List – For quick access, all of the best and most popular objects in the Advanced GT database have

been broken down into lists based on their type and/or common name:

Named Stars

Named Objects

Double Stars

Variable Stars

Asterisms

CCD Objects

IC Objects

Abell Objects

Constellation

5. Info: Displays coordinates and useful information about objects selected from the Advanced GT database.

6. Tour: Activates the tour mode, which seeks out all the best objects for the current date and time, and automatically slews the telescope to those objects.

7. Enter: Pressing Enter allows you to select any of the Advanced GT functions and accept entered parameters.

8. Undo: Undo will take you out of the current menu and display the previous level of the menu path. Press Undo repeatedly to get back to a main menu or use it to erase data entered by mistake.

9. Menu: Displays the many setup and utilities functions such as tracking rates and user defined objects and many others.

10. Scroll Keys: Used to scroll up and down within any of the menu lists. A double-arrow will appear on the right side of the LCD when there are sub-menus below the displayed menu. Using these keys will scroll through those sub-menus.

11. Rate: Instantly changes the rate of speed of the motors when the direction buttons are pressed.

12. RS-232 Jack: Allows you to interface with a computer and control the telescope remotely.

Common name listing of the brightest stars in the sky. Alphabetical listing of over 50 of the most popular deep sky objects. Numeric-alphabetical listing of the most visually stunning double, triple and quadruple stars in the sky. Select list of the brightest variable stars with the shortest period of changing magnitude. A unique list of some of the most recognizable star patterns in the sky. A custom list of many interesting galaxy pairs, trios and clusters that are well suited for CCD imaging with the Advanced GT telescope. A complete list of all the Index Catalog deep-sky objects. A custom list of the Abell Catalog deep-sky galaxies. A complete list of all 88 constellations.

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This section describes the basic hand control procedures needed to operate the GT Series Telescopes. These procedures are grouped into three categories: Alignment, Setup and Utilities. The alignment section deals with the initial telescope alignment as well as finding objects in the sky; the setup section discusses changing parameters such as tracking mode and tracking rate; finally, the last section reviews all of the utilities functions such as calibrating your mount, polar alignment and backlash compensation.

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In order for the telescope to accurately point to objects in the sky, it must first be aligned to three known positions (stars) in the sky. With this information, the telescope can create a model of the sky, which it uses to locate any object with known coordinates. There are many ways to align your telescope with the sky depending on what information the user is able to provide: Auto Align allows the telescope to select three stars and uses the entered time/location information to align the telescope; Auto Three Star Align involves the same process as Auto Align, however it allows the user to select which star to use to align the telescope. Quick-Align will ask you to input all the same information as you would for the Auto Align procedure. However, instead of slewing to the alignment stars for centering and alignment, the telescope bypasses this step and simply models the sky based on the information given. Finally, Last Alignment restores your last saved star alignment and switch position. Last Alignment also serves as a good safeguard in case the telescope should lose power.

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Before any of the described alignments are performed, the telescope mount needs to be positioned so that the index marks are aligned on both the right ascension and declination axes (see Fig 2-8). First index its switch position so that each axis has an equal amount of travel to move in either direction. Once the index position has been set,

Mount Calibration

the hand control will display the last entered date and time information stored in the hand control. Once the telescope is powered on:

1. Press ENTER begin the alignment process.

2. The hand control will ask the user to set the mount to its index

position. Move the telescope mount, either manually or with the hand control, so that the index marked in both R.A. and Dec are aligned (see Fig 2-8). Press Enter to continue.

3. The hand control will then display the last entered local time,

date, time zone, longitude and latitude.

• Use the Up/Down keys (10) to view the current parameters.

• Press ENTER to accept the current parameters.

• Press UNDO to enter current date and time

information into the hand control. The following information will be displayed:

Time - Enter the current local time for your area. You can enter either the local time (i.e. 08:00), or you can enter military time (i.e. 20:00 ).

• Select PM or AM. If military time was entered,

the hand control will bypass this step.

• Choose between Standard time or Daylight

Savings time. Use the Up and Down scroll buttons

fter an Auto Align is successfully completed, the hand control will display the message, Calibrating...

This automatic calibration routine is necessary to calculate and compensates for "cone" erro inherent in all German equatorial mounts. Cone error is the inaccuracy that results from the optical tube not being exactly perpendicular to the mounts declination axis as well as various other inaccuracies such as backlash in the mounts gears. The telescope is able to automatically determine the cone error value by always using alignment stars on both sides of the Meridian (see Figure 3-2). Mechanical errors can be reduced further by always centering alignment stars using the up and right arrow buttons as described in the Pointing Accuracy box below.

(10) to toggle between options.

• Select the time zone that you are observing from. Again, use the Up and Down buttons (10) to

scroll through the choices. Refer to Time Zone map in Appendix for more information.

Date - Enter the month, day and year of your observing session.

• Finally, you must enter the longitude and latitude of the location of your observing site. Use

the table in Appendix C to locate the closest longitude and latitude for your current observing location and enter those numbers when asked in the hand control, pressing ENTER after each entry. Remember to select "West" for longitudes in North America and "North" for latitudes in the North Hemisphere. For international cities, the correct hemisphere is indicated in the Appendix listings.

4. Select one of the four alignment methods as described below.

Note: If incorrect information is entered into the hand control, the UNDO button acts like a back space button

allowing the user to re-enter the correct data.

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Auto Align allows the telescope to automatically choose three stars (two on one side of the Meridian, and one on the opposite side) on which to align itself. To Auto Align your telescope:

1. Select Auto Align from the alignment choices given. Based on the date and time information entered, the telescope will automatically select and go to a bright star that is above the horizon.

• If for some reason the chosen star is not visible

(perhaps behind a tree or building) press UNDO to automatically select the next bright star from the database star list.

2. Once the telescope is finished slewing to your first alignment star, the display will ask you to use the arrow buttons to align the selected star with the crosshairs in the center of the finderscope. Once centered in the finder, press ENTER.

3. The display will then instruct you to center the star in the field of view of the eyepiece. When the star is centered, press ALIGN to accept this star as your first alignment star.

The Meridian is an imaginary line in the sky that starts at the North celestial pole and ends at the South celestial pole and passes through the zenith. If you are facing South, the meridian starts from your Southern horizon and passes directly overhead to the North celestial pole.

Figure 3-2

4. After the first alignment star has been entered the telescope will automatically select a second alignment star on the same side of the Meridian and have you repeat this procedure for that star.

5. For the third alignment star, the telescope will select a bright star on the opposite side of the Meridian and slew to it. Once again center the star in the crosshairs of the finderscope and then center the star in the eyepiece, pressing ENTER when complete.

When the telescope has been aligned on all three stars the display will read Alignment Successful, and you are now ready to find your first object.

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Auto Three-Star Alignment works much the same way as Auto Align, however instead of automatically slewing to the alignment stars, the user is allowed to select the alignment stars from a list. To use Auto Three-Star Align:

1. Select Auto Three Star Align from the alignment choices given.

2. The hand control will display a recommended alignment star to

begin.

• Press UNDO to display the next recommended star on the same

side of the Meridian, or

• Press the UP and DOWN arrows keys to scroll through the

compete list of available alignment stars to choose from.

3. Once the desired alignment star is displayed on the hand control

press ENTER to slew the telescope to the star.

Pointing Accuracy

For the best possible pointing accuracy, always center the alignment stars using the up arrow button and the right arrow button.

pproaching from this direction when looking through the eyepiece will eliminate much of the backlash between the gears and assures the most accurate alignmen possible.

4. As with the Auto Align procedure, you will be asked to center the star in the crosshairs of the finderscope and then center the star in the eyepiece, pressing ENTER when complete.

NOTE: Although the telescope allows the user to select the alignment stars, for best all-sky pointing accuracy it is still necessary to select two alignment stars on one side of the Meridian and the third star on the opposite side of the Meridian. For this reason, the hand control will only display stars that are on the same side of the Meridian for the first two alignment stars, then will only display stars on the opposite side of the Meridian for the third alignment star.

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Quick-Align uses all the date and time information entered at startup to align the telescope. However, instead of slewing to the alignment stars for centering and alignment, the telescope bypasses this step and simply models the sky based on the information given. This will allow you to roughly slew to the coordinates of bright objects like the moon and planets and gives the telescope the information needed to track objects in any part of the sky (depending on accuracy of polar alignment). Quick-Align is not meant to be used to accurately locate small or faint deep-sky objects or to track objects accurately for photography.

To use Quick-Align, simply select Quick Align from the alignment options and press ENTER. The telescope will automatically use the entered date/time parameters to align itself with the sky and display Alignment Successful.

NOTE: Once a Quick-Align has been done, you can use the Re-alignment feature (see below) to improve your telescopes pointing accuracy.

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The Last Alignment method will automatically recall the last stored index positions to continue using the alignment that was saved when the telescope was last powered down. This is a useful feature should your telescope accidentally lose power or be powered down.

NOTE: Just like with Quick-Align, you can use the Re-alignment feature (see below) to improve your telescopes pointing accuracy after using the Last Alignment method. To maintain a more accurate alignment over a series of observing sessions, use the Hibernate feature described later in this chapter.

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The Advanced Series telescopes have a re-alignment feature which allows you to replace any of the original

• If you are observing over a period of a few hours, you may notice that your original two alignment

• If you have aligned your telescope using the Quick-Align method, you can use re-align to align on

To replace an existing alignment star with a new alignment star:

1. Select the desired star (or object) from the database and slew to it.

2. Carefully center the object in the eyepiece.

3. Once centered, press the UNDO button until you are at the main menu.

4. With Advanced GT displayed, press the ALIGN key on the hand control.

5. The display will then ask you which alignment star you want to replace. Use the UP and Down scroll keys to select the alignment star to be replaced. It is usually best to replace the star closest to the new object. This will space out your alignment stars across the sky.

6. Press ALIGN to make the change.

alignment stars with a new star or celestial object. This can be useful in several situations:

stars have drifted towards the west considerably. (Remember that the stars are moving at a rate of 15º every hour). Aligning on a new star that is in the eastern part of the sky will improve your pointing accuracy, especially on objects in that part of the sky.

actual objects in the sky. This will improve the pointing accuracy of your telescope without having to re-enter addition information.

Helpful

Hint

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Selecting an Object

Now that the telescope is properly aligned, you can choose an object from any of the catalogs in the telescope's extensive database. The hand control has a key (4) designated for each of the catalogs in its database. There are two ways to select objects from the database: scrolling through the named object lists and entering object numbers.

Pressing the LIST key on the hand control will access all objects in the database that have common names or types. Each list is broken down into the following categories: Named Stars, Named Object, Double Stars,

Variable Stars, Asterisms and CCD Objects. Selecting any one of these catalogs will display a numeric-

alphabetical listing of the objects under that list. Pressing the Up and Down keys (10) allows you to scroll through the catalog to the desired object.

When scrolling through a long list of objects, holding down either the Up or Down key will allow you to scroll

through the catalog more rapidly by only displaying every fifth catalog object.

Pressing any of the other catalog keys (M, CALD, NGC, or STAR) will display a blinking cursor below the name of the catalog chosen. Use the numeric key pad to enter the number of any object within these standardized catalogs. For example, to find the Orion Nebula, press the "M" key and enter "042".

Slewing to an Object

Once the desired object is displayed on the hand control screen, choose from the following options:

• Press the INFO Key. This will give you useful information about the selected object such as R.A.

and declination, magnitude size and text information for many of the most popular objects.

• Press the ENTER Key. This will automatically slew the telescope to the coordinates of the object.

Caution: Never slew the telescope when someone is looking into the eyepiece. The telescope can move at fast

slew speeds and may hit an observer in the eye.

Object information can be obtained without having to do a star alignment. After the telescope is powered on, pressing any of the catalog keys allows you to scroll through object lists or enter catalog numbers and view the information about the object as described above.

Finding Planets

Your telescope can locate all 8 of our solar systems planets plus the Moon. However, the hand control will only display the solar system objects that are above the horizon (or within its filter limits). To locate the planets, press the PLANET key on the hand control. The hand control will display all solar system objects that are above the horizon:

• Use the Up and Down keys to select the planet that you wish to observe.

• Press INFO to access information on the displayed planet.

• Press ENTER to slew to the displayed planet.

Tour Mode

The Advanced Series telescopes include a tour feature which automatically allows the user to choose from a list of interesting objects based on the date and time in which you are observing. The automatic tour will display only those objects that are within your set filter limits (see Filter Limits in the Setup Procedures section of the manual). To activate the Tour mode, press the TOUR key (6) on the hand control. The hand control will display the best objects to observe that are currently in the sky.

• To see information and data about the displayed object, press the INFO key.

• To slew to the object displayed, press ENTER.

• To see the next tour object, press the Up key.

Constellation Tour

In addition to the Tour Mode, your telescope has a Constellation Tour that allows the user to take a tour of all the best objects in each of the 88 constellations. Selecting Constellation from the LIST menu will display all the constellation names that are above the user defined horizon (filter limits). Once a constellation is selected, you can choose from any of the database object catalogs to produce a list of all the available objects in that constellation.

• To see information and data about the displayed object, press the INFO key.

• To slew to the object displayed, press ENTER.

• To see the next tour object, press the Up key.

Direction Buttons

The hand control has four direction buttons (3) in the center of the hand control which control the telescope's motion in altitude (up and down) and azimuth (left and right). The telescope can be controlled at nine different speed rates.

Rate Button

Pressing the RATE key (11) allows you to instantly change the speed rate of the motors from high speed slew rate to precise guiding rate or anywhere in between. Each rate corresponds to a number on the hand controller key pad. The number 9 is the fastest rate (3º per second, depending on power source) and is used for slewing between objects and locating alignment stars. The number 1 on the hand control is the slowest rate (.5x sidereal) and can be used for accurate centering of objects in the eyepiece and photographic guiding. To change the speed rate of the motors:

• Press the RATE key on the hand control. The LCD will display the current speed rate.

• Press the number on the hand control that corresponds to the desired speed. The number will

appear in the upper-right corner of the LCD display to indicate that the rate has been changed.

The hand control has a "double button" feature that allows you to instantly speed up the motors without having to choose a speed rate. To use this feature, simply press the arrow button that corresponds to the direction that you want to move the telescope. While holding that button down, press the opposite directional button. This will increase the slew rate to the maximum slew rate.

The direction that a star moves in the eyepiece when a direction is pressed will change depending on which side of the Meridian the telescope tube is positioned. In order to change the direction of the arrow buttons, see Scope Setup Features later in this section.

1 = .5x 6 = 64x 2 = 1x (sidereal) 7 = .5º / sec 3 = 4x 8 = 2º / sec 4 = 8x 9 = 3º / sec 5 = 16x

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The Advanced GT contains many user defined setup functions designed to give the user control over the telescope's many advanced features. All of the setup and utility features can be accessed by pressing the MENU key and scrolling through the options:

Nine available slew speeds

Tracking Mode This allows you to change the way the telescope tracks depending on the type of mount

being used to support the telescope. The telescope has three different tracking modes:

EQ North

EQ South

Off

Used to track the sky when the telescope is polar aligned in the Northern Hemisphere.

Used to track the sky when the telescope is polar aligned in the Southern Hemisphere.

When using the telescope for terrestrial (land) observation, the tracking can be turned off so that the telescope never moves.

Tracking Rate In addition to being able to move the telescope with the hand control buttons, your

telescope will continually track a celestial object as it moves across the night sky. The tracking rate can be changed depending on what type of object is being observed:

Sidereal

Lunar

Solar

This rate compensates for the rotation of the Earth by moving the telescope at the same rate as the rotation of the Earth, but in the opposite direction. When the telescope is polar aligned, this can be accomplished by moving the telescope in right ascension only.

Used for tracking the moon when observing the lunar landscape.

Used for tracking the Sun when solar observing with the proper filter.

View Time-Site - Displays the current time and longitude/latitude downloaded from the optional CN-16 GPS

receiver. It will also display other relevant time-site information like time zone, daylight saving and local sidereal time. Local sidereal time (LST) is useful for knowing the right ascension of celestial objects that are located on the Meridian at that time. View Time-Site will always display the last saved time and location entered while it is linking with the GPS. Once current information has been received, it will update the displayed information. If GPS is switched off or not present, the hand control will only display the last saved time and location.

User Defined Objects - Your telescope can store up to 400 different user defined objects in its memory. The

objects can be daytime land objects or an interesting celestial object that you discover

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Celestron C10-NGT User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual