User manual ORION TELESCOPES & BINOCULARS SKYQUEST XT10

[. . . ] INSTRUCTION MANUAL Orion SkyQuest XT10 ® TM #9810 Dobsonian Reflecting Telescope Customer Support (800) 676-1343 E-mail: support@telescope. com Corporate Offices (831) 763-7000 Providing Exceptional Consumer Optical Products Since 1975 P. O. Box 1815, Santa Cruz, CA 95061 IN 179 Rev. B 09/03 Secondary mirror holder with 4-vane spider (not visible) Finder scope Finder scope bracket Eyepiece Navigation knob Focus knob Optical tube Altitude side bearing CorrecTension (XT) Friction Optimization system Right side panel Front brace Eyepiece rack Handle Primary mirror cell Top baseplate Left side panel Ground baseplate Figure 1. The SkyQuest XT10 Foot (3) 2 Welcome to an exciting new world of adventure! [. . . ] If the entire primary mirror reflection is not visible in the secondary mirror, as in Figure 14c; you will need to adjust the tilt of the secondary mirror. This is done by alternately loosening one of the three alignment set screws while tightening the other two, as depicted in Figure 16. The goal is to center the primary mirror reflection in the secondary mirror, as in Figure 14d. Don't worry that the reflection of the secondary mirror (the smallest circle, with the collimation cap "dot" in the center) is off-center; you will fix that in the next step. Figure 16. Adjust the tilt of the secondary mirror by loosening or tightening the three alignment screws with a 2mm hex key. Adjusting the Primary Mirror The final adjustment is made to the primary mirror. It will need adjustment if, as in Figure 14d, the secondary mirror is centered under the focuser and the reflection of the primary mirror is centered in the secondary mirror, but the small reflection of the secondary mirror (with the "dot" of the collimation cap) is off-center. The tilt of the primary mirror is adjusted with three springloaded collimation thumbscrews on the back end of the optical tube (bottom of the primary mirror cell); these are the larger thumbscrews. The other three smaller thumbscrews lock the mirror's position in place; these thumbscrews must be loosened before any collimation adjustments can be made to the primary mirror. To start, turn the smaller thumbscrews that lock the primary mirror in place a few turns each (Figure 17). Use a screwdriver in the slots, if necessary. Now, try tightening or loosening one of the larger collimation thumbscrews with your fingers (Figure 18). The three thumb screws that lock the primary mirror in place must first be loosened before any adjustments can be made. 11 focuser and see if the secondary mirror reflection has moved closer to the center of the primary. You can tell this easily with the collimation cap and mirror center mark by simply watching to see if the "dot" of the collimation cap is moving closer or further away from the "ring" on the center of the primary mirror mark. When you have the dot centered as much as is possible in the ring, your primary mirror is collimated. The view through the collimation cap should resemble Figure 14e. A simple star test will tell you whether the optics are accurately collimated. Note About the Collimatable 2" Focuser (XT8) The 2" focuser of the SkyQuest XT8 can be collimated using three pairs of push-pull screws located at the base of the focuser. The focuser was collimated at the factory however, and should never need to be adjusted. Focuser collimation is only required under very rare circumstances, but has been made available for this telescope should such a need arise. Star-Testing the Telescope When it is dark, point the telescope at a bright star and accurately center it in the eyepiece's field-of-view. Slowly defocus the image with the focusing knob. If the telescope is correctly collimated, the expanding disk should be a perfect circle (Figure 19). [. . . ] Now, remove the mirror from the mirror cell by first removing the four mirror clips that secure the mirror in its cell. Use a Phillips screwdriver to unthread the mirror clip anchor screws. Next, hold the mirror by its edge, and remove it from the mirror cell. Be careful not to touch the aluminized surface of the mirror with your fingers! [. . . ]