Celestron NexStar 8 Instruction Manual
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Celestron NexStar 8 Instruction Manual

Celestron nexstar 8: user guide
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Summary of Contents for Celestron NexStar 8

  • Page 2: Table Of Contents

    Goto Alt-Az...20 Utility Features ...20 Demo ...20 RS-232...20 Light Control...20 Cord Wrap...20 Anti-backlash ...20 TELESCOPE BASICS ...22 Image Orientation ...22 Focusing ...23 Calculating Magnification ...23 Determining Field of View ...23 General Observing Hints ...24 ASTRONOMY BASICS...25 The Celestial Coordinate System ...25 Motion of the Stars ...26...
  • Page 3 Short Exposure Prime Focus Photography...32 Eyepiece Projection...33 Long Exposure Prime Focus Photography ...34 Terrestrial Photography...35 CCD Imaging ...36 TELESCOPE MAINTENANCE ...37 Care and Cleaning of the Optics...37 Collimation...37 OPTIONAL ACCESSORIES ...39 APPENDIX A - TECHNICAL SPECIFICATIONS...42 APPENDIX B – GLOSSARY OF TERMS...43 APPENDIX C –LONGITUDES AND LATITUDES...46...

  • Page 4: Introduction

    Congratulations on your purchase of the Celestron NexStar! The NexStar ushers in a whole new generation of computer automated technology. Simple and friendly to use, the NexStar is up and running after locating just two alignment stars. It’s the perfect combination of power and portability. If you are new to astronomy, you may wish to start off by using the NexStar's built-in Sky Tour feature, which commands the NexStar to find the most interesting objects in the sky and automatically slews to each one.

  • Page 5: Quick Setup

    AC outlet. Power the NexStar by flipping the "On/Off" switch to the "On" position. *Note: Use only the AC adapter supplied by Celestron. Using any other adapter may damage the electronics and will void your manufacturer's warranty. On / Off Switch Use the Up and Down scroll buttons to get to the AutoAlign menu.
  • Page 6 The NexStar will automatically pick an alignment star and slew the telescope close to that star. Once there, the display will ask you to use the arrow buttons to aim the Star Pointer at the star. If the star is not visible (perhaps behind a tree), press UNDO to select a new star.

  • Page 7: On/Off Switch

    Figure 1-A - The NexStar 8 Optical Tube Star Pointer Finderscope Eyepiece Star Diagonal Focuser Knob Battery Compartment Tripod ON/OFF Switch Hand Control Liquid Crystal Display...

  • Page 8: A S S E M B L I N G T H E N E X S T A R

    Start by removing the telescope from its shipping carton and setting the round base on a flat table or surface. It is best to carry the telescope by holding it from the lower portion of the fork arm and from the bottom of the base. Do not try to move the optical tube at this time.

  • Page 9: Attaching The Nexstar To The Tripod

    The Celestron NexStar tripod is a sturdy, lightweight mount on which to place your NexStar telescope. Weighing less than 10 pounds, this tripod can go anywhere, from your backyard to a remote observing site. To set up the tripod: Hold the tripod with the head up, away from the ground.

  • Page 10: The Star Diagonal

    • Use the Up arrow directional button to move the telescope tube until it is roughly parallel to the ground. This will make it more convenient to attach the necessary accessories as well as remove the front lens cover and install batteries when they are needed.

  • Page 11: The Star Pointer Finderscope

    The Star Pointer is the quickest and easiest way to point your telescope exactly at a desired object in the sky. It's like having a laser pointer that you can shine directly onto the night sky. The Star Pointer is a zero magnification pointing tool that uses a coated glass window to superimpose the image of a small red dot onto the night sky.
  • Page 12 If the Star Pointer is perfectly aligned, you will see the red LED dot overlap the alignment star. If the Star Pointer is not aligned, take notice of where the red dot is relative to the bright star. Without moving the main telescope, turn the Star Pointer's azimuth and altitude alignment controls until the red dot is directly over the alignment star.

  • Page 13: Hand Control

    Align: Instructs the NexStar to use a selected star or object as an alignment position. Direction Keys: Allow complete control of the NexStar in any direction. Use the direction keys to move the telescope to the initial alignment stars or for centering objects in the eyepiece.

  • Page 14: Hand Control Operation

    Once the telescope is powered on, the LCD display will guide you through all the steps to align the telescope properly. Before the telescope is ready to be aligned, it should be set up in an outside location with all accessories (eyepiece, diagonal and Star Pointer) attached and lens cover removed as described in the Assembly section of the manual.
  • Page 15 NexStar will automatically choose two stars for alignment and roughly center the stars in the field of view of the Star Pointer. Once again the telescope should be set up outside with all accessories attached and the lens cover removed.

  • Page 16: Third Star Alignment

    Press ENTER to make the change. Now that the telescope is properly aligned, you can choose an object from any of the catalogs in the NexStar'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.

  • Page 17: Slewing To An Object

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

  • Page 18: Direction Buttons

    While holding that button down, press the opposite directional button. This will increase the slew rate to approximately 1.5º per second (equal to rate 7 on the hand control). This feature will not function if the telescope is currently set at a speed rate of 8 or The slower slew rates (6 and lower) move the motors in the opposite direction than the faster slew rates (8 and 9).

  • Page 19: Tracking Rate

    The NexStar stores celestial objects to its database by saving its right ascension and declination in the sky. This way the same object can be found each time the telescope is aligned. Once a desired object is centered in the eyepiece, simply scroll to the "Save Sky Obj"...

  • Page 20: Rs-232

    Cord Wrap – Cord wrap safeguards against the telescope slewing more than 360º in azimuth and wrapping the power cord around the base of the telescope. By default wrap should be turned off when powering the NexStar with batteries.
  • Page 21 N exS tar R eady M ENU A L IG NM ENT T R ACK IN G M OD E AU T O ALIG N A L T -A Z P O IN T T U B E N O R T H & L E V E L E Q N O R T H E Q S O U T H M M /DD/YY...

  • Page 22: 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 23: Focusing

    480 power. Although this is the maximum useful magnification, most observing is done in the range of 20 to 35 power for every inch of aperture which is 160 to 280 times for the NexStar 8 telescope.

  • Page 24: General Observing Hints

    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.

  • Page 25: 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 26: 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 27: Polar Alignment (With Optional Wedge)

    Even though the NexStar can precisely track a celestial object while in the Alt-Az position, it is still necessary to align the polar axis of the telescope (the fork arm) to the Earth's axis on rotation in order to do long exposure astro photography.

  • Page 28: Finding The North Celestial Pole

    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.

  • Page 29: 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 30: Observing The Sun

    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 31: Seeing

    Seeing conditions refers to the stability of the atmosphere and directly affects 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.

  • Page 32: Celestial Photography

    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 33: Eyepiece Projection

    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.

  • Page 34: Long Exposure Prime Focus Photography

    The best method for long exposure deep sky astro photography is with an off-axis guider. This device allows you to photograph and guide through the telescope simultaneously. 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.

  • Page 35: Terrestrial Photography

    For this purpose, Celestron offers the Micro Guide Eyepiece (#94171) Here is a brief summary of the technique. Polar align the telescope using an optional equatorial wedge. Remove all visual accessories.

  • Page 36: Reducing Vibration

    Due to the relative small size of the CCD chip, the field of view when imaging will be less than the field of view of a film camera. Using Celestron's optional f/6.3 Reducer/Corrector accessory in conjunction with a CCD camera (or film camera) will greatly increase the photographic field of view and...

  • Page 37: Telescope Maintenance

    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 38 (see figure 9-2). 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.

  • Page 39: Optional Accessories

    Celestron offers SMA eyepieces in 1-1/4" sizes in the following focal lengths: 6mm, 10mm, 12mm, • Ultima - Ultima is not really a design, but a trade name for our 5-element, wide field eyepieces. In the 1-1/4"...
  • Page 40 1/4" barrel diameter, they are available in the following focal lengths: 2.5mm, 4mm, 5mm, 6mm, 9mm, 10mm, 12mm and 15mm. Celestron also offers the LV Zoom eyepiece (#3777) with a focal length of 8mm to 24mm. It offers an apparent field of 40º...
  • Page 41 Skylight Filter (#93621) - The Skylight Filter is used on the Celestron NexStar 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 42: Appendix A - Technical Specifications

    Near Focus standard eyepiece or camera Field of View: Standard Eyepiece : 35mm Camera Linear Field of View (at 1000 yds) Magnification: Standard Eyepiece : Camera Optical Tube Length Weight of Telescope Electronic Specifications Input Voltage Maximum Minimum Batteries Required Power Supply Requirements...

  • Page 43: 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 44 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 45 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. Waning Moon The period of the moon's cycle between full and new, when its illuminated portion is decreasing.

  • Page 46: Appendix C -Longitudes And Latitudes

    LONGITUDE LATITUDE degrees degrees ALABAMA Anniston 34.8 Auburn 26.4 40.2 Birmingham 34.2 Centreville Dothan 19.2 Fort Rucker 43.2 16.8 Gadsden 58.2 Huntsville 46.2 Maxwell AFB 22.2 22.8 Mobile 40.8 Mobile Aeros 37.8 Montgomery Muscle Shoal 37.2 Selma 59.4 20.4 Troy 52.2 Tuscaloosa 37.2...
  • Page 47 LONGITUDE LATITUDE degrees degrees Melbourne 37.8 Miami 16.8 49.2 Naples Nasa Shuttle 40.8 37.2 Orlando 19.2 25.8 Panama City 40.8 Patrick AFB 13.8 Pensacola 19.2 Ruskin 58.2 Saint Peters 40.8 55.2 Sanford 46.8 Sarasota Tallahassee 22.2 22.8 Tampa Intl 31.8 58.2 Titusville 31.2...
  • Page 48 LONGITUDE LATITUDE degrees degrees Wurtsmith Ypsilanti 31.8 13.8 MINNESOTA Albert Lea 22.2 40.8 Alexandria 22.8 52.2 Bemidji Muni 55.8 Brainerd-Crw Detroit Laks 52.8 49.2 Duluth 10.8 49.8 49.2 Fairmont 25.2 Fergus Falls Grand Rapids 31.2 13.2 Hibbing 22.8 Intl Falls 22.8 34.2 Litchfield...
  • Page 49 LONGITUDE LATITUDE degrees degrees OKLAHOMA Altus AFB 16.2 40.2 Ardmore Bartlesville Clinton Enid 22.8 Fort Sill Gage 46.2 Hobart Lawton 25.2 34.2 Mcalester 46.8 52.8 Norman 28.2 13.8 Oklahoma Page 37.2 40.8 Ponca City 43.8 Stillwater Tinker AFB 22.8 25.2 Tulsa Vance AFB 55.2...
  • Page 50 LONGITUDE LATITUDE degrees degrees Walla Walla 16.8 Wenatchee Whidbey Is Yakima 31.8 WEST VIRGINIA Beckley Bluefield 13.2 Charleston Clarksburg 13.8 Elkins Huntington Lewisburg Martinsburg 58.8 Morgantown 55.2 Parkersburg 25.8 Wheeling Wh Sulphur CITY PROVINCE LONGITUDE Calgary Alberta Churchill Newfoundland Coppermine Northwest Terr.

  • Page 51: Appendix D - Rs-232 Connection

    – Direction buttons Allowing you to move the telescope in both directions • – Rate changes Allows you to change the telescope's rate of speed when using the direction • – Undo Use to escape from RS-232 mode Protocol: NexStar5 communicates at 9600 bits/sec, No parity and stop bit Before all commands, the following INITIALIZATION is necessary: •...

  • Page 52: Appendix E - Maps Of Time Zones

    Appendix E – Maps of the Time Zones...
  • Page 60 CELESTRON ONE YEAR WARRANTY 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.
  • Page 61 Celestron International 2835 Columbia Street Torrance, CA 90503 Tel. (310) 328-9560 Fax. (310) 212-5835 Web site at http//www.celestron.com Copyright 1999 Celestron International All rights reserved. (Products or instructions may change without notice or obligation.) Item # 1101 1-INST $10.00 03/00...

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