instruction Manual Orion® 8" f/4.0 Newtonian Astrograph #9527 Providing Exceptional Consumer Optical Products Since 1975 OrionTelescopes.com Customer Support (800) 676-1343 • E-mail: support@telescope.com Corporate Offices (831) 763-7000 • 89 Hangar Way, Watsonville, CA 95076 IN 378 Rev.
Finder scope bracket 8x50 Finder scope Primary mirror cell DETAIL Dovetail finder scope base Focuser Tube rings Focus lock thumbscrew DETAIL Fine focus wheel Secondary mirror “spider” Focus wheel Focus wheel Drawtube tensioning thumbscrew 1.25" Adapter 2" Accessory collar Figure 1. The 8" f/4.0 Newtonian Astrograph Congratulations on your purchase of an Orion® 8" f/4.0 Newtonian Astrograph.
Focus lock thumbscrew Accessory lock thumbscrew 1.25" Adapter Accessory lock thumbscrew 2" Collar Accessory lock thumbscrew Brass compression ring Coarse focus wheel 10:1 Fine focus wheel Drawtube tensioning thumbscrew Coarse focus wheel Figure 2. The dual-speed 2" Crayford-type linear bearing focuser are M6. It is likely that only the center hole will be needed to attach the rings to a dovetail plate for your mount or for your guide scope assembly. Balancing the 8" f/4.
Lock ring Tensioner O-ring (not visible) Black nylon thumbscrews Figure 3. The 8x50 finder scope and bracket assembly. Figure 4. Pull back the tensioner pin and slide the finder scope into its bracket until the O-ring is seated in the bracket ring. Using 1.25" and 2" Accessories The 2" focuser can accommodate both 1.25" and 2" accessories, including just about any eyepiece or camera. Both the 2" collar and removable 1.
Figure 5. Rear of telescope showing the installed cooling fan and six collimation adjustment knobs (three black collimation knobs and three white lock knobs). Black collimation knob (x3) Back of primary mirror Cooling fan White lock knob (x3) Power jack is centered on the crosshairs of the finder scope and in the telescope’s eyepiece, the finder scope is aligned and ready to be used for locating objects. The finder scope alignment should be checked before every imaging or observing session.
1.25" nosepiece T-ring Zero-profile camera adapter (not visible) Figure 6. To use a CCD camera with the 8" f/4.0 Newtonian Astrograph, the camera must have a 1.25" or 2" nosepiece, which is inserted into the appropriate accessory holder in the focuser. An external camera adapter with T-threads could be used in lieu of the nosepiece. Figure 7.
drawtube Reflective surface of collimation cap Reflection of primary mirror clip b. a. d. Center ring on primary mirror c. e. Figure 9. Collimating the optics. (a) When the mirrors are properly aligned, the view down the focuser drawtube should look like this. (b) With the collimation cap in place, if the optics are out of alignment, the view might look something like this.
Figure 12. To center the secondary mirror axially under the Figure 11. Placing a piece of white paper inside the optical tube opposite the focuser provides a bright background when viewing into the focuser. NOTE: The center ring sticker need not ever be removed from the primary mirror. Because it lies directly in the shadow of the secondary mirror, its presence in no way adversely affects the optical performance of the tele scope or the image quality.
rotate slightly when tightening the screw, so keep at it until the mirror faces the focuser squarely and is secured in place. Spider vane thumb nuts Figure 12. To center the secondary mirror axially under the focuser, hold the secondary mirror holder in place with your fingers while adjusting the center screw with a large Phillips-head screwdriver. Later you will adjust the tilt of the secondary mirror by turning the three small set screws that surround the large center screw. Figure 13.
Out of collimation Collimated Figure 14. A star test will determine if the telescope’s optics are properly collimated. A defocused view of a bright star through the eyepiece should appear as illustrated on the right if the optics are perfectly collimated. If the circle is unsymmetrical, as illustrated on the left, the optics need alignment. The view through the collimation cap should now resemble Figure 9e. A simple star test will indicate how well the telescope optics are collimated.
the Phillips-head screw is unthreaded, the secondary mirror and its holder can be removed from the telescope. The secondary mirror does not need to be removed from its holder for cleaning. Then follow the same procedure described below for cleaning the primary mirror. To clean the primary mirror, first carefully remove the mirror cell from the telescope. To do so you must remove the six screws on the exterior of the mirror cell (Figure 15). Then pull the cell away from the tube.
One-Year Limited Warranty The Orion 8" f/4.0 Newtonian Astrograph is warranted against defects in materials or workmanship for a period of one year from the date of purchase. This warranty is for the benefit of the original retail purchaser only. During this warranty period Orion Telescopes & Binoculars will repair or replace, at Orion’s option, any warranted instrument that proves to be defective, provided it is returned postage paid to: Orion Warranty Repair, 89 Hangar Way, Watsonville, CA 95076.
