Celestron 8i manual

I I N N S S T T R R U U C C T T I I O O N N M M A A N N U U A A L L[...]

INTRODUCTION ................................................................................................................... ............ 4 W W A A R R N N I I N N G G ..................................................................................................................................................... 4 QUICK SETUP ..............[...]

3 ASTRONOMY BASICS ............................................................................................................... .... 28 The Celestial Coordinate System ................................................................................................ ........... 28 Motion of the Stars................................................[...]

4 Congratulations on your purchase of the Celestron NexStar! The NexStar i-series telescopes are precision scientific instruments tha t will a llow you to enjoy viewin g numerous objects in the night sky — planets, nebulae, star clusters, galaxies and mor e. Equipped with high speed mot ors and hand control, the NexStar-i allows you to remotely m[...]

5 1 Optical Tube 7 Accessory Tary 2 Star Pointer Finderscope 8 Tripod 3 Eyepiece 9 ON/OFF Switch / 12v power 4 Star Diagonal 10 Fork Arm 5 Focuser Knob 11 Hand Control 6 Battery Compartment 12 Schmidt Corrector Plate (not sho w n) Figure 1-A - The NexStar 8i SE 1 2 3 4 5 11 10 9 12 6 7 8[...]

7 A) Attach the included acces sories. Loosen the thumb screw s on the side of the visual back and remove the protecti ve plastic cap. Insert the star diagonal and e yepiece into the barrel of the visual back and tigh ten down all thumb screws. B) Twist and remo ve the front lens cover from the end of the telescope. C) Attach the Star Pointer and t[...]

8 5 6 7 8 With the NexStar powered on, press ENTER to begin an alig nment. Up and Down Scroll Buttons Direction Buttons a) Use the Up and Down scroll buttons to get to the Auto Two-Star Align menu and press ENTER. b) Input the necessary date and time information as instructed by the hand control. (See Hand Control section for complete instruction o[...]

9 The NexStar comes completely pre-ass embled and can be operational in a matter of minutes. The NexStar and its accessories are convenientl y packaged in one reusable shipping carton that contains t he following accessories: • 25mm Plossl Eyepiece – 1¼" • Star Diagonal - 1¼" • Star Pointer Finderscope and Mounting Bracket • V[...]

10 P P o o w w e e r r i i n n g g t t h h e e N N e e x x S S t t a a r r The NexStar c an be powered by eight user supplied AA batteries or with an optional AC adapter or cigarette lighter adapter. The batter y compartment is located in the center of the telescope's base (see figure 1-3). To power the NexStar with batteries: 1. Slowly rotate[...]

11 T T h h e e E E y y e e p p i i e e c c e e The eyepiece, or ocular, is the optical element that magnifies the image focused by the telescope. T he eyepiece fits into either the visual back directly or the star diagonal. To install the eyepiece: 1. Loosen the thumbscrew on the star diagonal so it does not obstruct the inner diameter of the eyepi[...]

12 2. Locate the square dovetail bracket that has the proper curvature for the NexSt ar tube and align the holes with the two holes in the telescope body. 3. Use the two 8-32 x ¼" scre ws to tighten down the bracket to the rear cell. 4. Once the bracket is mounted, slide the mounting track at the bottom of the Star Pointer over the dovet ail [...]

13 The NexStar Computerize d Hand Control gives you inst ant access to all the functions your telesco pe has to offer. With automatic slewing to over 40,000 objects, and common sense menu descriptions, ev en a beginner can master its variety of features in just a few observing sessions. Belo w is a brief description of the individual components of [...]

14 4. Catalog Keys: The NexStar has keys on the hand co ntrol to allow direct access to each of the catalogs in its database. The NexStar contains the follo wing catalogs in its database: Messier – Complete list of all Messier objects. NGC – Complete list of all the deep-sky objects in the Revised Ne w General Catalog. Caldwell – A combinatio[...]

15 A A l l i i g g n n m m e e n n t t P P r r o o c c e e d d u u r r e e s s In order for the NexStar to accurately point to objects in the sky, it must first be aligned to two 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. T here a[...]

16 Based on this information, the NexStar will automatically select a second bright star that is above the horizon and slew towards it. At this point the telescope is only roughly al igned, so the alignment star should o nly be near the field of view of the Star Pointer finderscope. Once finishe d slewing, the display will ask you to use the arro w[...]

17 EQ North / EQ South Alignment EQ North and EQ South Alignments assist the user i n aligning the telescope when polar align ed on an optional equatorial wedge. Just as with the Altazimuth alignments desc ribed earlier, the EQ alignments gives you th e choice of performing an Aut oAlign or a Two-Star alignment. • The EQ AutoAlign follows many of[...]

18 Pressing the LIST ke y on the hand control will access all objects in the datab ase 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 an y one of these catalogs will display a numeric- alphabetical listing of the o[...]

19 D D i i r r e e c c t t i i o o n n B B u u t t t t o o n n s s The NexStar has four direction buttons (3) i n the center of the hand control which control the telescope's motion in altitude (up and do wn) and azimuth (left and right). T he telescope can be contro lled at nine different speed rates. R R a a t t e e B B u u t t t t o o n n P[...]

20 EQ North Used to track the sky when the telescope is polar align ed using an equatorial wedge in the Northern Hemisphere. EQ South Used to track the sky when the telescope is polar align ed using an equatorial wedge in the Southern Hemisph ere. Off When using the telescope for terrestrial (land) observation, the tracking can be turned off so tha[...]

21 To replace the contents of any of the user defined objects, simply save a new object using one of the e xisting identification numbers; NexStar will replace the prev ious user defined object with the current one. Get RA/DEC - Displays the right ascensi on and declination for the current positi on of the telescope. Goto R.A/ Dec - Allows you to i[...]

22 the drive control keys can be changed. To reverse t he button logic of the hand control, press the MENU button and select Direction B uttons from the Utilities menu. Use the Up/Do wn arrow keys (10) to select either the azimuth (left and right) or altit ude (up and down) button direction and press ENTER. Pressing E NTER again wil l reverse the d[...]

23 Goto Alt-Az - Allows you to enter a specific altitude and azimuth position and sle w to it. Hibernate - Hibernate allows t he NexStar to be complet ely powered down and still re tain its alignment when turned back on. This not only saves power, but is ideal for those th at have their telescopes permanentl y mounted or leave their telesc ope in o[...]

24 NexStar Menu Tree: The following figure is a menu tree sho w ing the sub-menus a ssociated with the primary command functions ALT- A Z EQ NORTH EQ SOUT H OF F MOD E SIDE REAL SOLA R LUN AR RATE TRACKING VIEW TIME-SITE SETUP TIM E-SITE A NTI-BACKL ASH SLEW LI MIT S FIL TER L IMITS DIRECTIO N BUTTO N S GOTO AP PROAC H A UTOG UIDE RATE CORDW RAP SC[...]

25 Figure 3-1 A A c c u u t t a a w w a a y y v v i i e e w w o o f f t t h h e e l l i i g g h h t t p p a a t t h h o o f f t t h h e e S S c c h h m m i i d d t t - - C C a a s s s s e e g g r r a a i i n n o o p p t t i i c c a a l l d d e e s s i i g g n n Actual image orientation as seen with the unaided eye Inverted image, as viewed with the[...]

26 F F o o c c u u s s i i n n g g The NexStar's focusing mec hanism controls the primar y mirror which is mounted on a ring that slides back an d forth on the primary baffle tube. The focusing kn ob, which moves the primar y mirror, is on the rear cell of the telescope j ust below the star diagonal and eyep iece. Turn the focusing knob until [...]

27 distance of one thousan d yards. The appar ent field of each eyepiece t hat Celestron manufactures is found in the Celestron Accessory Catalog (#93685). G G e e n n e e r r a a l l O O b b s s e e r r v v i i n n g g H H i i n n t t s s When working with any optical instrument, there are a few things to remember to ensu re you get the best possi[...]

28 Up to this point, this manual covered the assembly and bas ic operation of your NexStar telescope. However, to understand your t elescope more thoroughly , you need to know a little about the night sk y. This section deals with obs ervational astronomy in ge neral and includes inform ation on the night sky and polar alignment. T T h h e e C C e [...]

29 M M o o t t i i o o n n o o f f t t h h e e S S t t a a r r s s The daily motion of the Sun across the sky is familiar to even the m ost casual observer. This daily trek is not the Sun moving as early astronomers thought, but the re sult of the Earth's rotation. T he Earth's rotation also causes the stars to do the same, scribing out a[...]

30 P P o o l l a a r r A A l l i i g g n n m m e e n n t t ( ( w w i i t t h h o o p p t t i i o o n n a a l l W W e e d d g g e e ) ) Even though the NexStar can precisely track a celestial object while in the Alt-Az position, it is still necessar y to align the polar axis of the telescope (the fork arm) to the Earth's axis of rotation in ord[...]

31 F F i i n n d d i i n n g g t t h h e e N N o o r r t t h h C C e e l l e e s s t t i i a a l l P P o o l l e e 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 hemis phere in whic h they reside. For example, in the northern hemisp[...]

32 With your telescope set up, you are ready to use it for observing. T his 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. O O b b s s e e r r v v i i n n g g t t h h e e M M o o o o n n Often, it is tempting to look at the Moon when[...]

33 Never project an image of th e Sun through the telescope. Becaus e of the folded optical design, tremen dous heat build-up will result inside the optical tube. This can damage the t elescope and/or an y accessories attached to the telescope. For safe solar viewing, use a solar filter that reduc es the intensity of the Sun's light, making it[...]

34 The amount of bendi ng depends on air densit y. Varying temperature layers hav e different densities and, therefore, bend light differently. Light rays from th e same object arrive slightly displaced creati ng an imperfect or smeared image. These atmospheric dist urbances vary from time-to-time a nd place-to-place. The size of the air parcels co[...]

35 After looking at the night sky for a while you may want to try photographing it. Several forms of celestial photography ar e possible with your te lescope, including short e xposure prime focus, eyepi ece projection, long exposure dee p sky, terrestrial and even CCD imaging. Each of these is discuss ed in moderate detai l with enough information[...]

36 • T-Max 100 • T-Max 400 • Any 100 to 400 ISO color slide film • Fuji Super HG 400 • Ektar 25 or 100 2. Center the Moon in the field of your NexStar telescope. 3. Focus the telescope by turning the focus knob until the imag e is sharp. 4. Set the shutter speed to the appropriate setting (see table below). 5. Trip the shutter using a cab[...]

37 and not touching it. It is easier if you use t wo people for this process; one to release the camera shutter and one to hold the card. Here's the process for making the exposure. 7. Find and center the desired target in the viewfinder of your camera. 8. Turn the focus knob until the image is as sharp as possi ble. 9. Place the black card ov[...]

38 There are several techni ques for this type of photography, and the one chose n will determine the standard accessories needed. T he best method for long exposure deep sky astro photography is with an off-axis guider. This device all ows you to photogra ph and guide through th e telescope simultaneously. Cel estron offers a very special and adva[...]

39 T T e e r r r r e e s s t t r r i i a a l l P P h h o o t t o o g g r r a a p p h h y y Your NexStar 8i makes an excellent 200 0mm telephoto lens for terrestrial (land) photogr aphy (The NexStar 5i would be equivalent to a 1250mm lens). T errestrial photography is best done w ill the telescope in Alt-Az configuration and the tracking drive turne[...]

40 While your NexStar telescope requ ires little maintenance, there are a few things to remember that will ensure your telescope performs at its best. C C a a r r e e a a n n d d C C l l e e a a n n i i n n g g o o f f t t h h e e O O p p t t i i c c s s Occasionally, dust and/or moisture may build up o n the corrector plate of your telescope. Spec[...]

41 Figure 7-3 A collimated telescope should appear symmetrical with the central obstruction centered in the star's diffraction pattern. To verify collimation, view a star near the zenith. Use a m edium to high power ocular — 12mm to 6mm focal length. It is important to center a star in the center of the field to judge collim ation. Slowly cr[...]

42 Perfect collimation will yield a star image very symmetrical just inside and outsid e of focus. In addition, perfect collimation delivers the optim al optical performance specifications that yo ur telescope is built to achieve. If seeing (i.e., air steadiness) is tur bulent, collimation is difficu lt to judge. Wait until a better night if it is [...]

43 You will find t hat additional accessories enhance your v iewing pleasure a nd expand the usefulnes s of your telescope. For ease of reference, all the accessories are list ed in alphabetical order. Adapter AC (#18773) - Allow DC (battery powered) telescopes to be converted for use with 120 volt AC power. Adapter, Car Battery (#18769) - Celestro[...]

44 widest possible field of vie w with a 1-1/4" diagonal and is ideal for the NexStar with or without the Reducer/Corrector. • X-CEL - Fully Multi-coated. All air-to-glass surfaces hav e 5 layer multi-coating. Field of view 55°. Six element optical design using ED glass on most curved elem ents. Parfocal – little to no focusing adjustment[...]

45 and eyepiece hous ing rotate independentl y of the camera orientation making th e acquisition of a guide star quite easy. Second, the prism an gle is tunable allowing you t o look at guide stars on-axis. This accessory works especially well with the Reducer/Corrector. Reducer/Corrector (#94175) - T his lens reduces the focal length of the telesc[...]

46 A A P P P P E E N N D D I I X X A A – – T T E E C C H H N N I I C C A A L L S S P P E E C C I I F F I I C C A A T T I I O O N N S S Optical Specification 11022-XLT-SE NexStar 8i Design Schmidt-Cassegrain Catadioptric Aperture 8 inches (203.2mm) Focal Length 80 inches (2032mm) F/ratio of the Optic al System 10 Primary Mirror: Material Coa tin[...]

47 Complete Messier Catalog 110 Complete IC Catalog 5,386 Complete Caldwell 109 Solar System objects 9 Abell Galaxies 2,712 Famous Asterisms 20 Selected CCD Imaging Objects 25 Selected SAO Stars 29,500 Total Object Database 45,492[...]

48 A A p p p p e e n n d d i i x x B B – – G G l l o o s s s s a a r r y y o o f f T T e e r r m m s s A- Absolute magnitude The apparent magnitude that a star wo uld 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. at a distance of 10 parsecs, it would just be visi[...]

49 Focal length The distance bet ween 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. J - Jovian Planets Any of the four gas giant planets that are at a greater distance form the sun than the terrestrial planet[...]

50 resolution. Right Ascension: (RA) the angular distance of a celestial object measured in hour s, minutes, and seconds along the Celestial Equator eastward from the Vernal Equinox. S - Schmidt Telescope Rated the most important advance in optics in 200 years, the Schmidt telescope combines the best features of the refractor and reflector for phot[...]

51 A A P P P P E E N N D D I I X X C C L L O O N N G G I I T T U U D D E E S S A A N N D D L L A A T T I I T T U U D D E E S S LONGITUDE LATITUDE degrees min degrees min AL ABAM A Anniston 85 51 33 34.8 Auburn 85 26.4 32 40.2 Birmingham 86 45 33 34.2 Centreville 87 15 32 54 Dothan 85 27 31 19.2 Fort Rucker 85 43.2 31 16.8 Gadsden 86 5.4 33 58.2 Hun[...]

52 LONGITUDE LATITUDE degrees min degrees min Melbourne 80 37.8 28 6 Miami 80 16.8 25 49.2 Naples 81 4.8 26 7.8 Nasa Shuttle 80 40.8 28 37.2 Orlando 81 19.2 28 25.8 Panama City 85 40.8 30 12 Patrick AFB 80 3.6 28 13.8 Pensacola 87 19.2 30 21 Ruskin 82 3.6 27 58.2 Saint Peters 82 40.8 27 55.2 Sanford 81 15 28 46.8 Sarasota 82 33 27 24 Tallahassee 84[...]

53 LONGITUDE LATITUDE degrees min degrees min Wurtsmith 83 2.4 44 27 Ypsilanti 83 31.8 42 13.8 MINNESOTA Albert Lea 93 22.2 43 40.8 Alexandria 95 22.8 45 52.2 Bemidji Muni 94 55.8 47 30 Brainerd-Crw 94 7.8 46 24 Detroit Laks 95 52.8 46 49.2 Duluth 92 10.8 46 49.8 Ely 91 49.2 47 54 Fairmont 94 25.2 43 39 Fergus Falls 96 4.2 46 18 Grand Rapids 93 31.[...]

54 LONGITUDE L ATITUDE degrees min degrees min OKLAHOMA Altus AFB 99 16.2 34 40.2 Ardmore 97 1.2 34 18 Bartlesville 96 0 36 45 Clinton 99 1.2 35 21 Enid 97 4.8 36 22.8 Fort Sill 98 2.4 34 39 Gage 99 46.2 36 18 Hobart 99 3 35 0 Lawton 98 25.2 34 34.2 Mcalester 95 46.8 34 52.8 Norman 97 28.2 35 13.8 Oklahoma 97 3.6 35 24 Page 94 37.2 34 40.8 Ponca Ci[...]

55 LONGITUDE L ATITUDE degrees min degrees min Walla Walla 118 16.8 46 6 Wenatchee 120 1.2 47 24 Whidbey Is 122 39 48 21 Yakima 120 31.8 46 34.2 WEST VIRGINIA Beckley 81 7.2 37 46.8 Bluefield 81 13.2 37 18 Charleston 81 3.6 38 22.2 Clarksburg 80 13.8 39 16.8 Elkins 79 51 38 52.8 Huntington 82 33 38 22.2 Lewisburg 80 2.4 37 52.2 Martinsburg 77 58.8 [...]

56 A A p p p p e e n n d d i i x x D D - - R R S S - - 2 2 3 3 2 2 C C o o n n n n e e c c t t i i o o n n You can control your NexStar 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 NexStar can be controlled using popular astronomy software programs. C[...]

57 A A P P P P E E N N D D I I X X E E – – M M A A P P S S O O F F T T I I M M E E Z Z O O N N E E S S[...]

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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 repla[...]

Celestron 2835 Columbia Street Torrance, CA 90503 Tel. (310) 328-9560 Fax. (310) 212-5835 Web site at http//www.celestron.com Copyright 2004 Celestron All rights reserved. (Products or instru ctions may change without notice or obligation.) Item # 11022-XLT-SE-INST 11-04 $10.00[...]