Celestron CG-4 Instruction Manual

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- 10 - AAttttaacchhiinngg tthhee CCeenntteerr LLeegg BBrraaccee Figure 2-6 1. Remove the accessory tray

- 11 - Since the fully assembled telescope can be quite heavy, position the mount so that the polar axis is pointing towards north before the tube a

- 12 - 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

- 13 - IInnssttaalllliinngg tthhee FFiinnddeerrssccooppee To install the finderscope onto the telescope you must first mount the finderscope thr

- 14 - IInnssttaalllliinngg tthhee SSttaarr DDiiaaggoonnaall The Star Diagonal is a prism that diverts the light at a right angle to the light

- 15 - The refracting telescopes can use eyepieces and diagonals of a 2” barrel diameter. To use a 2” barrel eyepiece, the 1¼” eyepiece adapter mus

- 16 - BBaallaanncciinngg tthhee MMoouunntt iinn DDEECC The telescope should also be balanced on the declination axis to prevent any sudden mo

- 17 - AAddjjuussttiinngg tthhee MMoouunntt iinn AAllttiittuuddee • To increase the latitude of the polar axis, tighten the rear latitude adj

- 18 - A telescope is an instrument that collects and focuses light. The nature of the optical design determines how the light is focused. Som

- 19 - Figure 3-3 AA ccuuttaawwaayy vviieeww ooff tthhee lliigghhtt ppaatthh ooff tthhee SScchhmmiiddtt--CCaasssseeggrraaiinn ooppttiiccaall

2 TTaabbllee ooff CCoonntteennttss INTRODUCTION ...

- 20 - Actual image orientation as seen with the unaided eye Inverted image, normal with Newtonians and as viewed with eyepiece directly in other sc

- 21 - AAlliiggnniinngg tthhee FFiinnddeerrssccooppee Accurate alignment of the finder makes it easy to find objects with the telescope, especia

- 22 - DDeetteerrmmiinniinngg FFiieelldd ooff VViieeww Determining the field of view is important if you want to get an idea of the angular si

23 Up to this point, this manual covered the assembly and basic operation of your telescope. However, to understand your telescope more thoroug

24MMoottiioonn ooff tthhee SSttaarrss The daily motion of the Sun across the sky is familiar to even the most casual observer. This daily trek

25LLaattiittuuddee SSccaallee The easiest way to polar align a telescope is with a latitude scale. Unlike other methods that require you to find

26 Figure 4-4 Remember, while Polar aligning, DO NOT move the telescope in R.A. or DEC. You do not want to move the telescope itse

27 PPoollaarr AAlliiggnnmmeenntt iinn tthhee SSoouutthheerrnn HHeemmiisspphheerree Polar alignment to the South Celesti

28 Pointing at Sigma Octantis This method utilizes Sigma Octantis as a guidepost to the celestial pole. Since Sigma Octantis is about 1° degree fr

29DDeecclliinnaattiioonn DDrriifftt MMeetthhoodd ooff PPoollaarr AAlliiggnnmmeenntt This method of polar alignment allows you to get the

3 Transparency ...

30AAlliiggnniinngg tthhee RR..AA.. SSeettttiinngg CCiirrccllee Before you can use the setting circles to find objects in the sky you need to a

318. Lock the R.A. clamp to prevent the telescope from slipping in R.A. The telescope will track in R.A. as long as the motor drive is operating.

32 With your telescope set up, you are ready to use it for observing. This section covers visual observing hints for solar system and deep sky o

33OObbsseerrvviinngg tthhee SSuunn Although overlooked by many amateur astronomers, solar observation is both rewarding and fun. However, becau

34SSeeeeiinngg Seeing conditions refers to the stability of the atmosphere and directly affects the amount of fine detail seen in extended objects

35 After looking at the night sky for a while you may want to try photographing it. Several forms of photography are possible with your telescop

364. Set the shutter speed to the “B” setting and focus the lens to the infinity setting. 5. Locate the area of the sky that you want to photogra

372. Center the Moon in the field of your telescope. 3. Focus the telescope by turning the focus knob until the image is sharp. 4. Set the shutte

381. Find and center the desired target in the viewfinder of your camera. 2. Turn the focus knob until the image is as sharp as possible. 3. Plac

39Note: Digital Cameras – follow the camera instructions on focusing and shutter data. 1. Polar align the telescope. For more information on pol

- 4 - Congratulations on your purchase of an Omni XLT Series telescope. The Omni XLT Series of telescopes come in several different models: 102m

40CCCCDD IImmaaggiinngg ffoorr DDeeeepp SSkkyy OObbjjeeccttss Special cameras have been developed for taking images of deep sky images. Thes

41 While your telescope requires little maintenance, there are a few things to remember that will ensure your telescope performs at its best.

42Pick a bright star and center it in the field of the telescope. Study the image of the star while racking it in and out of focus using an eyep

43 Before you begin the collimation process, be sure that your telescope is in thermal equilibrium with the surroun

44 Perfect collimation will yield a star image very symmetrical just inside and outside of focus. In addition, per

45Newtonian collimation views as seen through the focuser using the collimation cap Secondary mirror needs adjustment Primary mirror n

46Night Time Star Collimating After successfully completing daytime collimation, night time star collimation can be done by closely adjusting the

47 When satisfied with the collimation, tighten the small locking screws. Take note of the direction the light appears to flare. For exampl

48 You will find that additional accessories for your Omni telescope will enhance your viewing pleasure and expand the usefulness of your telesco

49Flashlight, Night Vision - (# 93588) - Celestron’s premium model for astronomy, using two red LED's to preserve night vision better than red

- 5 - Figure 1-1 Omni XLT 102 Refractor (Omni XLT 102ED, Omni XLT 120 and

50Reducer/Corrector (# 94175) - This lens reduces the focal length of the SCT telescope by 37%, making your Omni XLT127 a 788mm f/6.3 instrument.

51Appendix A Technical Specifications Omni XLT Series 21088 21092 21090 21094 31057 11084 Omni XLT 102 Omni XLT 102ED Omni XLT 12

52AAppppeennddiixx BB -- GGlloossssaarryy ooff TTeerrmmss A- Absolute Magnitude The apparent magnitude that a star would have if it were

53F - Focal Length The distance between a lens (or mirror) and the point at which the image of an object at infinity is brought to focus. The fo

54R - Reflector A telescope in which the light is collected by means of a mirror. Resolution The minimum detectable angle an optical system c

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- 6 - Figure 1-2 Omni XLT 150 Newtonian 1. Finderscope 7. 1.75" Steel Tripod 2. Finderscope Brac

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61 CCeelleessttrroonn TTwwoo YYeeaarr WWaarrrraannttyy A. Celestron warrants this telescope to be free from defects in materials and workm

Celestron 2835 Columbia Street Torrance, CA 90503 U.S.A. Tel. (310) 328-9560 Fax. (310) 212-5835 Website www.celest

- 7 - Figure 1-3 Omni XLT 127 Schmidt-Cassegrain 1. Optical Tube 7. 1.75" Steel Tripod 2. Finderscope 8. Counterweights 3. Findersco

- 8 - This section covers the assembly instructions for your Celestron Omni XLT telescope. The equatorial mount is exactly the same for all th

- 9 - AAttttaacchhiinngg tthhee EEqquuaattoorriiaall MMoouunntt The equatorial mount allows you to tilt the telescope’s axis of rotation so tha