User manual ORION TELESCOPES & BINOCULARS SKYQUEST6&8 REVB

[. . . ] INSTRUCTION MANUAL Orion SkyQuest XT6 & XT8 ® #9806 and #9808 Dobsonian Reflecting Telescopes Customer Support (800) 676-1343 E-mail: support@telescope. com Corporate Offices (831) 763-7000 Providing Exceptional Consumer Optical Products Since 1975 P. O. B 09/03 Secondary mirror with 4-vane spider (not shown) Finder scope Finder scope bracket Navigation knob Eyepiece Focus knob Optical tube Right side panel Altitude side bearing Front brace Handle Pull loop Eyepiece rack Top baseplate Left side panel Ground baseplate CorrecTension Friction Optimization System Figure 1. The SkyQuest XT Dobsonian (XT6 pictured) 2 Your SkyQuest Dobsonian is a high-quality optical instrument designed to bring you dazzling views of the outer reaches of our universe. Easy enough for kids to use, and portable enough for anyone to carry, the SkyQuest will provide fun and entertainment for the entire family. [. . . ] Using a 2mm hex key, loosen the three small alignment set screws in the center hub of the 4-vaned spider several turns. Now hold the mirror holder stationary (be careful not to touch the surface of the mirrors), while turning the center screw with a Phillips head screwdriver (see Figure 13). Turning the screw clockwise will move the secondary mirror toward the front opening of the optical tube, while turning the screw counter-clockwise will move the secondary mirror toward the primary mirror. Note: When making these adjustments, be careful not to stress the spider vanes or they may bend. When the secondary mirror is centered in the focuser drawtube, rotate the secondary mirror holder until the reflection of the primary mirror is as centered in the secondary mirror as possible. Now tighten the three small alignment screws equally to secure the secondary mirror in that position. If the entire primary mirror reflection is not visible in the secondary mirror, as in Figure 12c, you will need to adjust the tilt of the secondary mirror. This is done by alternately loosening one of the three alignment setscrews while tightening the other two, as depicted in Figure 14. The goal is to center the primary mirror reflection in the secondary mirror, as in Figure 12d. Don't worry that the reflection of the secondary mirror (the smallest circle, with the collimation cap "dot" in the center) is off-center. Adjust the tilt of the secondary mirror by loosening or tightening the three alignment set 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 12d, 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. Now, try tightening or loosening one of the larger collimation thumbscrews with your fingers (Figure 16). Look into the 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 farther away from the ring on the center of the primary mirror. Figure 13. To center the secondary mirror under the focuser, hold the secondary mirror holder in place with one hand while adjusting the center bolt with a Phillips screwdriver. The three small thumbscrews that lock the primary mirror in place must first be loosened before any adjustments can be made. 11 When you have the dot centered as much as possible in the ring, your primary mirror is collimated. A simple star test will tell you whether the optics are accurately collimated. Out of collimation Collimated Figure 17. [. . . ] To clean the primary mirror, carefully remove the mirror cell from the telescope. To do this, you must remove the screws that connect the entire mirror cell to the steel tube. Now, remove the mirror from the mirror cell by removing the three mirror clips that secure the mirror in its cell. Use a Phillips head screwdriver to unthread the mirror clip anchor screws. [. . . ]