Orion #8297 8" F/3.9 manual

INSTRUCTION MANUAL IN 406 Re v . A 07/11 Customer Support (800) 676- 1 343 • E-mail: support@telescope.com C o rp o r at e O ff i c es ( 83 1 ) 76 3 - 7 00 0 • 89 Hangar W ay , W atsonville, CA 95076 © 2011 Orion T elescopes & Binoculars Orion 8" and 1 0" f/3.9 Newtonian Astr ographs #8297 8" f/3.9, #8296 10" f/3.9 Prov[...]

2 Congratulations on y our purchase of an Orion f/3.9 Ne wtonian Astrogr aph! These po werful imaging telescopes f eature “f ast, ” high-quality par abolic optics, a 2" dual-speed Cr a yf ord f ocuser , and e xcellent mechanical construction with some special f eatures . Optimized f or astrophotograph y with DSLR an d astronomical CCD imag[...]

3 packaging to ensure the telescope sta ys intact during shipping. T ake a moment to inspect the telescope and all of its par ts. Before pr oceeding with the instructions, refer to Figure 1 to familiarize your self with some of the features and com- ponents of the telescope. 1. Getting Star ted The telescope arrives nearly fully assembled from the [...]

4 Attaching the Finder Scope The included 9x50 crosshair finder scope (Figure 3a) is use- ful f or locating objects in the sky and centering them in the main telescope’ s field of vie w . T o install it, first remove the O-ring from the brac ket and place it ov er the body of the finder scope until it seats in the narro w groov e near the middle [...]

5 Cooling the T elescope All optical instruments need time to reach “thermal equilibri - um. ” The bigger the instrument and the larger the temperature change, the more time is needed. Allow at least 30 minutes f or your telescope to cool to the temper ature outdoors. In very cold climates (below freezing), it is essential to store the tele- sc[...]

6 Attaching a CCD Camera The Orion f/3.9 Newtonian Astrographs are equipped to accept CCD cameras with a 2" nosepiece, or a 2" coma cor - rector in place of the nosepiece, which slides directly into the telescope’ s f ocuser lik e an e yepiece (Figure 5). The 2" nosepiece is secured with the two thumbscre w locks . If your CCD imag[...]

7 cal tube in front of the f ocuser . Both the 8" and 10" models hav e added length in front of the f ocuser , compared to a stan- dard Newtonian, to pre v ent an y possibility of incoming light from impinging directly on the secondar y mirror or entering the f ocuser dra wtube. The baffle rings and the interior of the optical tube are bo[...]

8 The Collimation Cap Y our f/3.9 Newtonian Astrog raph comes with a “quic k collima- tion cap” (Figure 9) . This is a simple cap that fits on the f o - cuser dra wtube like a dust cap , but has a tiny hole in the cen- ter and a reflective inner surf ace. The collimation cap helps center your e y e ov er the f ocuser dra wtube so that aligning [...]

9 f or the time being. The secondary mirror itself should be cen- tered in the f ocuser dra wtube. If it is off-center along the axis of the telescope, i.e ., positioned too f ar tow ard the front open- ing or tow ard the rear of the telescope , as it is in Figure 8b , you will ha v e to adjust the mirror’ s axial position. T o do so, use a small[...]

10 of the three alignment set screws b y , sa y , one full tur n, and then tighten the other two to tak e up the slac k (Figure 13). Do not loosen the center screw during this process. The goal is to center the primar y mirror reflection in the secondary mir- ror , as in Figure 8d . When it is centered, y ou’ re done adjust - ing the secondar y m[...]

11 cap on the ey epiece opening. K eep the telescope inside the hard storage carrying case when not in use. Store it indoors or in a dry garage. Do not leave the telescope outside e xcept when using it. The optical tube is aluminum and has a smooth anodized surf ace that should resist scratches and sm udges. If a scratch does appear on the tube, it[...]

4. Specications Orion 8" f/3.9 Newtonian Astrograph Optical configuration: Newtonian reflector Aper ture: 203mm F ocal length: 800mm F ocal ratio: f/3.9 Primar y mirror: Low thermal expansion optical glass , parabolic figure Mirror coatings: Enhanced aluminum (94% reflectivity) with SiO 2 ov ercoat Secondar y mirror minor axis: 70mm F ocuse[...]