Celestron CGEM 1100 Instruction Manual
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Celestron CGEM 1100 Instruction Manual

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INSTRUCTION MANUAL
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Summary of Contents for Celestron CGEM 1100

  • Page 1 INSTRUCTION MANUAL ● ● ● ●...

  • Page 2: Table Of Contents

    Installing the Star Diagonal... 10 Installing the Eyepiece ... 10 Installing the Finderscope ... 11 Installing the CGEM 1100 Finderscope ... 11 Removing the Lens Cap ... 13 Moving the Telescope Manually ... 13 Balancing the Mount in R.A... 13 Balancing the Mount in DEC ...
  • Page 3 Set Mount Position ... 30 Set Mount Position... 30 Turn On/Off GPS ... 30 Turn On/Off RTC... 30 Periodic Error Correction ... 30 TELESCOPE BASICS... 32 Image Orientation... 32 Focusing ... 33 Calculating Magnification ... 33 Determining Field of View... 33 General Observing Hints ...

  • Page 4: Introduction

    Congratulations on your purchase of the Celestron CGEM Series telescope! The CGEM 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.
  • Page 5 Latitude Adjustment Knob Hand Control Tripod CONTROL PANEL On/Off Switch 12v Input Jack Figure 2.2 – CGEM (CGEM 1100 Shown) Tripod Center Leg Brace/Accessory Tray Counterweight(s) Counterweight Bar Azimuth Adjustment Knob Dovetail Mounting Bar Schmidt Corrector Lens Hand Control Port...

  • Page 6: Assembly

    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 telescope you must start with the tripod and work up from there. These instructions are laid out in the order each task must be performed.

  • Page 7: Attaching The Equatorial Mount

    Only thread the knobs about half way in, leaving enough space for the tripod Alignment Peg which will need to fit between the screw tips. 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 CGEM mount is a German equatorial mount that attaches to the tripod head.

  • Page 8: Attaching The Accessory Tray

    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.

  • Page 9: Attaching The Hand Control Holder

    The telescope comes 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...

  • Page 10: Attaching The Visual Back

    If you want to remove the visual back, rotate the slip ring counterclockwise until it is free of 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 physically more comfortable than if you looked straight through.

  • Page 11: Installing The Finderscope

    Find the two holes in the rear cell of the telescope on the top left, when looking from the back of the tube. 9x50 finderscope. The specifications for a finderscope stand for the magnification and the...
  • Page 12 Insert the screws through the bracket and into the rear cell. WARNING: If you remove the mounting bracket, do not completely thread the screws back into the rear cell of the telescope. The screws may be long enough to obstruct the movement of, and possibly damage the primary mirror.

  • Page 13: Removing The Lens Cap

    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. The amount of the imbalance is very slight.

  • Page 14: Balancing The Mount In Dec

    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.

  • Page 15: Adjusting The Mount In Azimuth

    The telescope mount 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.

  • Page 16: Hand Control

    All Celestron computerized telescope come with a hand control 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...

  • Page 17: Hand Control Operation

    In order for the telescope to accurately point to objects in the sky, it must first be aligned with 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.

  • Page 18: Startup Procedure

    Last Alignment also serves as a good safeguard in case the telescope should lose power. 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 3-2).

  • Page 19: Two Star Align

    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. Two-Star Align allows the user to select two stars on which to align the telescope. To align your telescope using the Two-Star Align method: Select Two-Star Align from the alignment choices given.

  • Page 20: Quick-Align

    To improve the telescope pointing accuracy, you can use the Re-Align feature as described below. 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.

  • Page 21: Last Alignment

    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.

  • Page 22: Slewing To An Object

    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).

  • Page 23: Direction Buttons

    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.

  • Page 24: Tracking Rate

    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 that is not included in the regular database.

  • Page 25: Get Ra/Dec

    Identify Identify Mode will search any of the telescope's database catalogs or lists and display the name and offset distances to the nearest matching objects. This feature can serve two purposes. First, it can be used to identify an unknown object in the field of view of your eyepiece.

  • Page 26: Anti-Backlash

    (right ascension) or altitude (declination) button direction and press ENTER. Select either positive or negative for both axes and press ENTER to save. Setting the azimuth button direction to positive will move the telescope in the same direction that the telescope tracks (i.e. towards the west). Setting the altitude buttons to positive will move the telescope counterclockwise along the DEC axis.

  • Page 27: Autoguide Rates

    Favor West – If the target object is accessible from both sides of the mount, selecting "Favor West" instructs the  telescope to point to the object as if it were on the west side of the meridian. The optical tube will then be positioned on the east side of the mount and pointing west.

  • Page 28: Ra Limits

    Meridian (ie. -20º on both sides) Warning: In order for the telescope to be able to slew to a star from the direction that minimizes the amount of backlash in the gears, it may be necessary for the telescope to slew beyond the specified slew limit in order to approach the star from the correct direction.

  • Page 29: Home Position

    To set the Home position for your mount simply use the arrow buttons on the hand control to move the telescope mount to the desired position. Select the Set option and press Enter.

  • Page 30: Scrolling Menu

    When you are ready to slew the telescope to your next object, just remember to manually return the tube to the same bright star and carefully center it in the eyepiece.
  • Page 31 MENU TRACKING MODE RATE VIEW TIME-SITE SCOPE SETUP SETUP TIME-SITE ANTI-BACKLASH FILTER LIMITS DIRECTION BUTTONS GOTO APPROACH AUTOGUIDE RATES OTA ORIENTATION MERIDIAN MOUNT SETTINGS R.A. LIMITS UTILITIES CALIBRATE MOUNT HOME POSITION LIGHTS CONTROL FACTORY SETTINGS VERSION GET AXIS POSITION GOTO AXIS POSITION HIBERNATE SUN MENU SCROLLING MENU...

  • Page 32: Telescope Basics

    A telescope is 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. Other telescopes, known as reflectors, use mirrors. The Schmidt- Cassegrain optical system (or Schmidt-Cass for short) uses a combination of mirrors and lenses and is referred to as a compound or catadioptric telescope.

  • Page 33: Focusing

    Let’s say, for example, you are using the 40mm Plossl eyepiece. To determine the magnification you simply divide the focal length of your telescope (the C8-S for example has a focal length of 2032mm) by the focal length of the eyepiece, 40mm.

  • Page 34: General Observing Hints

    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, while in some cases, you may actually see a double image.

  • Page 35: Astronomy Basics

    Up to this point, this manual covered the assembly and basic operation of your telescope. However, to understand your telescope more thoroughly, you need to know a little about the night sky. This section deals with observational astronomy in general and includes information on the night sky and polar alignment.

  • Page 36: Motion Of The Stars

    Motion of the Stars 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.

  • Page 37: Polar Aligning The Mount

    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.
  • Page 38 Updating your Star Alignment After polar alignment it's a good idea to check the pointing accuracy of the telescope to see how much it may have been affected by moving the mount. Since the polar alignment process requires you to "sync" the telescope on a bright star before you begin, it will be necessary to undo the sync before re-aligning.

  • Page 39: Finding The North Celestial Pole

    See figure 5-4 Loosen the DEC clutch knob and move the telescope so that the tube is perpendicular to the polar axis, ie, the tube should be pointing either due west or east.

  • Page 40: Celestial Observing

    With your telescope set up, you are ready to use it for observing. This section covers visual observing hints for both solar system and deep sky objects as well as general observing conditions which will affect your ability to observe.

  • Page 41: Solar Observing Hints

    The best time to observe the Sun is in the early morning or late afternoon when the air is cooler.  To center the Sun without looking into the eyepiece, watch the shadow of the telescope tube until it forms a circular shadow.
  • Page 42 Figure Seeing conditions directly affect image quality. These drawings represent a point source (i.e., star) under bad seeing conditions (left) to excellent conditions conditions produce images that lie some where right). Most often, seeing between these two extremes.

  • Page 43: Astrophotography

    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.).

  • Page 44: Eyepiece Projection

    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 to the visual back, and a T-ring for your particular camera make (i.e., Minolta, Nikon,...
  • Page 45 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;...

  • Page 46: Long Exposure Prime Focus Photography

    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.

  • Page 47: Periodic Error Correction (Pec)

    Hint Once the worm gear is indexed, it will not need to be positioned again until the telescope is turned-off. So, to give yourself more time to prepare for guiding, it may be necessary to restart PEC recording after the worm gear has found its index.

  • Page 48: Terrestrial Photography

    Point the telescope at the object you want to photograph and center the guide star on the illuminated cross hairs and you are ready to play back the periodic error correction. Once the drive's periodic error has been recorded, use the Playback function to begin playing back the correction for future photographic guiding.

  • Page 49: Ccd Imaging

    CCD Imaging SCT telescope's versatility allows it to be used in many different f-number configurations for CCD imaging. It can be used at f/6.3 (with the optional Reducer/Corrector), f/10, and f/20 (with the optional 2x Barlow) making it the most versatile imaging system available today.

  • Page 50: Telescope Maintenance

    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.
  • Page 51 (see figure 8-2). Center the de-focused star and notice in which direction the central shadow is skewed. Place your finger along the edge of the front cell of the telescope (be careful not to touch the corrector plate), pointing towards the collimation screws. The shadow of your finger should be visible when looking into the eyepiece.
  • Page 52 Perfect collimation will yield a star 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...

  • Page 53: Optional Accessories

    7mm, 10mm, 15mm, 19mm, 23mm, and 31mm. Filters Sets, Eyepiece - Celestron offers four convenient filter sets, which contain four different filters per set. Not only are these highly useful filter combinations, but they also offer an economical way to add versatility to your filter collection.
  • Page 54 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.
  • Page 55 Skylight Filter (#93621) - The Skylight Filter is used on the Celestron telescope as a dust seal. The filter threads onto the rear cell of your telescope. All other accessories, both visual and photographic (with the exception of Barlow lenses), thread onto the skylight filter.

  • Page 56: Appendix A - Technical Specifications

    2-Star Align, 1-Star Align, Solar System Align, Quick Align, Last Align 40,000+ objects, 400 user defined programmable objects. Enhanced information on over 200 objects 7,840 5,386 2,712 29,500 45,492 11099 CGEM 1100 280mm (11") Schmidt- Cassegrain 2800mm F/10 9x50 CGEM Computerized Equatorial 40mm Plossl (70x) 1.25"...

  • Page 57: Appendix B - Glossary Of Terms

    Sun against the stars". Equatorial mount A telescope mounting in which the instrument is set upon an axis which is parallel to the axis of the Earth; the angle of the axis must be equal to the observer's latitude.
  • Page 58 1 and those increasingly fainter from 2 down to magnitude 5. The faintest star that can be seen without a telescope is about magnitude 6. Each magnitude step corresponds to a ratio of 2.5 in brightness. Thus a star of magnitude 1 is 2.5 times brighter than a star of magnitude 2, and 100 times brighter than a magnitude 5 star.
  • Page 59 The rate is 15 arc seconds per second or 15 degrees per hour. Terminator boundary Universe The totality of astronomical things, events, relations and energies capable of being described objectively. Variable Star A star whose brightness varies over time due to either inherent properties of the star or something eclipsing or obscuring the brightness of the star.

  • Page 60: Appendix C - Rs-232 Connection

    Appendix C - RS-232 Connection You can control your telescope with a computer via the RS-232 port on the computerized hand control and using an optional RS-232 cable (#93920). Once connected, the telescope can be controlled using popular astronomy software programs.
  • Page 61 Additional RS232 Commands Multiply the desired tracking rate (arcseconds/second) by 4. Example: if the desired trackrate is 150 arcseconds/second, then TRACKRATE = 600 Separate TRACKRATE into two bytes, such that (TRACKRATE = TrackRateHigh*256 + rackRateLow). Example: TrackRateHigh = 2 TrackRateLow = 88 To send a tracking rate, send the following 8 bytes: Positive Azm tracking: Negative Azm tracking:80, 3, 16, 7, TrackRateHigh, TrackRateLow, 0, 0...

  • Page 62: Appendix D - Time Zone Map

    APPENDIX D – MAPS OF TIME ZONES...
  • Page 70 Celestron, is found to be defective in materials or workmanship. As a condition to the obligation of Celestron to repair or replace such product, the product must be returned to Celestron together with proof-of-purchase satisfactory to Celestron.
  • Page 71 Celestron 2835 Columbia Street Torrance, CA 90503 U.S.A. Tel. (310) 328-9560 Fax. (310) 212-5835 Web site at http//www.celestron.com Copyright 2008 Celestron All rights reserved. (Products or instructions may change without notice or obligation.) Item # 11097-INST $10.00 11-08 - Rev2...

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Cgem 800Cgem 925

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