INSTRUCTION MANUAL
INTRODUCTION .....................................................................................................................................................................4 WARNING ................................................................................................................................................................................4 ASSEMBLY .........................................................................................................................................
GPS On/Off......................................................................................................................................................................................22 Light Control ...................................................................................................................................................................................22 Factory Setting..........................................................................................................
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 three bright objects. 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.
1 2 3 12 11 4 5 6 10 9 7 8 1 Optical Tube 7 Tripod 2 Star Pointer Finderscope 8 Accessory Tray / Leg Brace 3 Eyepiece 9 Tilt Wedge Plate 4 Star Diagonal 10 ON/OFF Switch 5 Focuser Knob 11 Hand Control 6 Battery Compartment 12 Liquid Crystal Display NexStar 8 SE Shown 5
The NexStar 8 comes completely pre-assembled and can be operational in a matter of minutes.
The Star Diagonal The star diagonal diverts the light at a right angle from the light path of the telescope. For astronomical observing, this allows you to observe in positions that are more comfortable than if you were to look straight through. To attach the star diagonal: 1. Turn the thumbscrew on the visual back until its tip no longer extends into (i.e., obstructs) the inner diameter of the visual back. 2. Slide the chrome portion of the star diagonal into the visual back. 3.
3. Tighten the two screws on the side of the mounting track to secure the Star Pointer to the dovetail bracket. Star Pointer Operation The star pointer is powered by a long life 3-volt lithium battery (#CR2032) located underneath the front portion of the Star Pointer. Like all finderscopes, the Star Pointer must be properly aligned with the main telescope before it can be used. This is a simple process using the azimuth and altitude control knobs located on the side and bottom of the Star Pointer.
Attaching the NexStar to the Tripod The Celestron NexStar tripod is a sturdy, heavy duty mount on which to place your NexStar 6/8" telescope. This tripod can go anywhere, from your backyard to a remote observing site. The tripod comes completely assembled and only needs to have the center leg brace / accessory tray put in place. To set up the tripod: 1. Hold the tripod with the head up, away from the ground. 2.
The NexStar has a removable hand controller built into the side of the fork arm designed to give you instant access to all the functions the NexStar has to offer. With automatic slewing to 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 NexStar hand controller: 1. 2. 3.
4. Catalog Keys: The NexStar has a key on the hand control to allow direct access to each of the catalogs in its 40,000 object database. The NexStar contains the following catalogs in its database: Messier – Complete list of all Messier objects. NGC – Select 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 and Sun.
telescope. Finally, EQ North and EQ South alignments are designed to assist you in aligning the NexStar when polar aligned using the tripods built-in wedge. Each alignment method is discussed in detail below. Sky Align Sky Align is the easiest way to get your NexStar aligned and ready to observe. Even if you do not know a single star in the sky, the NexStar will have you aligned in minutes by asking for basic information like the date, time and location.
5. If the finderscope has been properly aligned with the telescope tube, the alignment star should now be visible inside the field of view of the eyepiece. The hand control will ask that you center the bright alignment star in the center of the eyepiece and press the ALIGN button. This will accept the star as the first alignment position. (There is no need to adjust the slewing rate of the motors after each alignment step.
• • Press the UNDO button to display the next most suitable star for alignment. Use the UP and DOWN scroll buttons to manually select any star you wish from the entire list of available stars. Once finished slewing, the display will ask you to use the arrow buttons to align the selected star with the red dot of the finderscope. Once centered in the finder, press ENTER. The display will then instruct you to center the star in the field of view of the eyepiece.
Solar System Align Solar System Align is designed to provide excellent tracking and GoTo performance by using solar system objects (Sun, Moon and planets) to align the telescope with the sky. Solar System Align is a great way to align your telescope for daytime viewing as well as a quick way to align the telescope for night time observing. 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. 1. 2.
slew the telescope to the displayed star. If for some reason you do not wish to select one of these stars (perhaps it is behind a tree or building), you can either: • • 7. 8. 9. Press the UNDO button to display the next most suitable star for alignment. Use the UP and DOWN scroll buttons to manually select any star you wish from the entire list of available stars. The telescope then asks you to center in the eyepiece the alignment object you selected.
Sync: The Sync feature can be used to improve pointing accuracy in a specific region of the sky. Sync is a very useful feature especially when used in conjunction with the Constellation tour and Identify feature in which you will be exploring smaller areas of the sky. To Sync on an object: 1. 2. 3. 4. 5. 6. Select the desired star (or object) from the database and slew to it. Once centered, press the UNDO button until you are at the main menu.
Slewing to an Object Once the desired object is displayed on the hand control screen, you have two options: • Press the INFO Key. This will give you useful information about the selected object such as magnitude, constellation and fascinating facts about many of the objects. • Press the ENTER Key. This will automatically slew the telescope to the coordinates of the object.
Direction Buttons The NexStar has four direction buttons in the center of the hand control which control the telescope motion in altitude (up and down) and azimuth (left and right). The telescope can be controlled at nine different speed rates. 1 2 3 4 5 = = = = = .
Sidereal Lunar Solar View Time-Site - 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. When mounted in AltAz mode, the telescope must make corrections in both R.A. and declination. Used for tracking the moon when observing the lunar landscape.
example, if your telescope is pointed at the brightest star in the constellation Lyra, choosing Identify and then searching the Named Star catalog will no doubt return the star Vega as the star you are observing. However, by selecting Identify and searching by the Named Object or Messier catalogs, the hand control will let you know that the Ring Nebula (M57) is approximately 6° from your current position. Searching the Double Star catalog will reveal that Epsilon Lyrae is only 1° away from Vega.
Slew Limits – Sets the limits in altitude that the telescope can slew without displaying a warning message. The slew limits prevent the telescope tube from slewing to an object below the horizon. The slew limits can be customized depending on your needs.
Goto Axis Position - Allows you to enter a specific altitude and azimuth position and slew to it. Hibernate - Hibernate allows the NexStar to be completely powered down and still retain its alignment when turned back on. This not only saves power, but is ideal for those that have their telescopes permanently mounted or leave their telescope in one location for long periods of time. To place your telescope in Hibernate mode: 1. Select Hibernate from the Utility Menu. 2.
NexStar SE MENU TRACKING MODE ALT-AZ EQ NORTH EQ SOUTH OFF RATE SIDEREAL SOLAR LUNAR VIEW TIME-SITE SCOPE SETUP SETUP TIME-SITE ANTI-BACKLASH SLEW LIMITS FILTER LIMITS DIRECTION BUTTONS GOTO APPROACH AUTOGUIDE RATES CORDWRAP UTILITIES GPS ON/OFF LIGHT CONTROL FACTORY SETTING VERSION GET AXIS POSITION GOTO AXIS POSITION HIBERNATE SUN MENU SCROLLING TEXT CALIBRATE GOTO SET MOUNT POSITION WEDGE ALIGN USER OBJECTS GOTO SKY OBJ SAVE SKY OBJ SAVE DB OBJ ENTER RA & DEC SAVE LAND OBJ GOTO LAND OBJ GET RA-DEC GOTO R
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.
Focusing The NexStar's focusing mechanism controls the primary mirror which is mounted on a ring that slides back and forth on the primary baffle tube. The focusing knob, which moves the primary mirror, is on the rear cell of the telescope just below the star diagonal and eyepiece. Turn the focusing knob until the image is sharp. If the knob will not turn, it has reached the end of its travel on the focusing mechanism. Turn the knob in the opposite direction until the image is sharp.
General Observing Hints When working with any optical instrument, there are a few things to remember to ensure you get the best possible image. • • • • Never look through window glass. Glass found in household windows is optically imperfect, and as a result, may vary in thickness from one part of a window to the next. This inconsistency can and will affect the ability to focus your telescope.
Up to this point, this manual covered the assembly and basic operation of your NexStar 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. The Celestial Coordinate System To help find objects in the sky, astronomers use a celestial coordinate system that is similar to our geographical coordinate system here on Earth.
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. The size of the circular path a star follows depends on where it is in the sky.
Polar Alignment 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 attempt long exposure astro photography. This is accomplished by using the built-in wedge attached to the steel tripod. This allows the telescope's tracking motors to rotate the telescope around the celestial pole, the same way as the stars.
Photography with the NexStar After looking at the night sky for a while you may want to try photographing it. In addition to the specific accessories required for celestial photography, there is the need for a camera - but not just any camera. The camera does not have to have many of the features offered on today's state-of-the-art equipment. For example, you don't need auto focus capability or mirror lock up. Here are the mandatory features a camera needs for celestial photography.
Finding the North Celestial Pole In each hemisphere, there is a point in the sky around which all the other stars appear to rotate. These points are called the celestial poles and are named for the hemisphere in which they reside. For example, in the northern hemisphere all stars move around the north celestial pole. When the telescope's polar axis is pointed at the celestial pole, it is parallel to the Earth's rotational axis.
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. Observing the Moon Often, it is tempting to look at the Moon when it is full. At this time, the face we see is fully illuminated and its light can be overpowering. In addition, little or no contrast can be seen during this phase.
Solar Observing Hints o o o 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. To ensure accurate tracking, be sure to select solar tracking rate. Observing Deep Sky Objects Deep-sky objects are simply those objects outside the boundaries of our solar system.
While your NexStar telescope requires little maintenance, there are a few things to remember that will ensure your telescope performs at its best. Care and Cleaning of the Optics Occasionally, dust and/or moisture may build up on the corrector plate of your telescope. Special care should be taken when cleaning any instrument so as not to damage the optics. If dust has built up on the corrector plate, remove it with a brush (made of camel’s hair) or a can of pressurized air.
Figure 8-2 -- Even though the star pattern appears the same on both sides of focus, they are asymmetric. The dark obstruction is skewed off to the left side of the diffraction pattern indicating poor collimation. To accomplish this, you need to tighten the secondary collimation screw(s) that move the star across the field toward the direction of the skewed light. These screws are located in the secondary mirror holder (see figure 8-1).
You will find that additional accessories enhance your viewing pleasure and expand the usefulness of your telescope. For ease of reference, all the accessories are listed in alphabetical order. Adapter, Car Battery (#18769) - Celestron offers the Car Battery Adapter that allows you to run the NexStar drive off an external power source. The adapter attaches to the cigarette lighter of your car, truck, van, or motorcycle.
lights. This includes mercury and high and low pressure sodium vapor lights. In addition, they also block unwanted natural light (sky glow) caused by neutral oxygen emission in our atmosphere. Celestron offers a model for 1-1/4" eyepieces (#94126A). Moon Filter (#94119-A) - Celestron’s Moon Filter is an economical eyepiece filter for reducing the brightness of the moon and improving contrast, so greater detail can be observed on the lunar surface.
Appendix A - Technical Specifications O Oppttiiccaall SSppeecciiffiiccaattiioonn Design Aperture Focal Length F/ratio of the Optical System Primary Mirror: Diameter Coatings Secondary Mirror Spot Size Secondary Obstruction Corrector Plate: Material Coatings Highest Useful Magnification Lowest Useful Magnification (7mm exit pupil) Resolution: Rayleigh Criterion Dawes Limit Light Gathering Power Near Focus standard eyepiece or camera Field of View: Standard Eyepiece Linear Field of View (at 1000 yds) Magnific
Appendix B - Glossary of Terms AAbsolute magnitude Airy disk Alt-Azimuth Mounting Altitude Aperture Apparent Magnitude Arcminute Arcsecond Asterism Asteroid Astrology Astronomical unit (AU) Aurora Azimuth BBinary Stars CCelestial Equator Celestial pole Celestial Sphere Collimation DDeclination (DEC) EEcliptic Equatorial mount The apparent magnitude that a star would have if it were observed from a standard distance of 10 parsecs, or 32.6 light-years. The absolute magnitude of the Sun is 4.8.
FFocal length JJovian Planets KKuiper Belt LLight-Year (ly) MMagnitude Meridian Messier NNebula North Celestial Pole Nova OOpen Cluster PParallax Parfocal Parsec Point Source RReflector The distance between a lens (or mirror) and the point at which the image of an object at infinity is brought to focus. The focal length divided by the aperture of the mirror or lens is termed the focal ratio.
Resolution Right Ascension: (RA) SSidereal Rate TTerminator UUniverse VVariable Star The minimum detectable angle an optical system can detect. Because of diffraction, there is a limit to the minimum angle, resolution. The larger the aperture, the better the resolution. The angular distance of a celestial object measured in hours, minutes, and seconds along the Celestial Equator eastward from the Vernal Equinox. This is the angular speed at which the Earth is rotating.
Appendix D – Maps of Time Zones 43
CELESTRON TWO YEAR WARRANTY A. Celestron warrants this telescope to be free from defects in materials and workmanship for two years. Celestron will repair or replace such product or part thereof which, upon inspection by 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. B.
Celestron 2835 Columbia Street Torrance, CA 90503 Tel. (310) 328-9560 Fax. (310) 212-5835 Web site at http//www.celestron.com Copyright 2006 Celestron All rights reserved. (Products or instructions may change without notice or obligation.) This device complies with Part 15 of the FCC Rule.
