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. Box 1815, Santa Cruz, CA 95061 IN 165 Rev. 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. [. . . ] 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. It may not be perfectly centered, but that is OK. 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. You will fix that in the next step. Figure 14. 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. To start, turn the smaller thumbscrews a few turns each (Figure 15). Use a screwdriver in the slots, if necessary. 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. Do not touch the mirror's surface! Figure 15. 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. [. . . ] Fill a clean sink, free of abrasive cleanser, with roomtemperature water, a few drops of liquid dishwashing detergent, and if possible, a capful of rubbing alcohol. Submerge the mirror (aluminized face up) in the water and let it soak for several minutes (or hours if it is a very dirty mirror). Wipe the mirror underwater with clean cotton balls, using extremely light pressure and stroking in straight lines across the surface. Use one ball for each wipe across the mirror. [. . . ]