User manual ORION TELESCOPES & BINOCULARS 03640

[. . . ] Good collimation is particularly critical for "faster" Newtonians, those with f-ratios of f/6 or lower. Once the collimation is set, it will hold if care is taken in transporting and handling the optical tube. However, any sharp jolts can knock the mirrors out of alignment, as can jostling of the scope in the trunk of a car or temperature changes over a period of time. Fortunately, these telescopes are equipped with adjustment screws that permit easy recollimation. Barrel (fits 1. 25" focusers) Crosshairs (for centering) Using the Collimating Eyepiece Collimation can be performed in daylight, when it is easier to see what you're doing. [. . . ] Check that the secondary (or diagonal) mirror is positioned in the center of the tube; use a ruler if necessary to measure the distance from the center of the secondary mirror holder to the inside of the tube on different sides. You may have to adjust the spider vanes or stalk. Also, check to see that the primary mirror is centered in the optical tube. A quick visual inspection usually suffices. If the primary is obviously not centered, it will need to be repositioned in its mirror cell. 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 070 0697 2. Next, if there is an eyepiece in the telescope, remove it. You will see the secondary mirror and mirror holder as well as reflections of the secondary mirror and its holder, the primary mirror, and your eye. It's pretty confusing, so refer to Figure 1 to sort them all out. (This figure shows what you would see if both the primary and secondary mirrors were out of alignment and the secondary mirror were not centered below the focuser tube. ) 3. Now insert the Collimating Eyepiece into the focuser and look into the sight hole. You'll notice that the field of view is narrower than it was when you were looking through the open focuser tube. You'll also notice that instead of seeing a reflection of your eye, you now see a bright annulus in the reflection of the secondary mirror. The annulus is the reflection of the polished 45° flat of the Collimating Eyepiece. Check whether the secondary mirror is centered underneath the focuser. Use the crosshairs at the bottom of the Collimating Eyepiece as a reference. The center of the secondary mirror should lie right at the intersection of the crosshairs. If it doesn't, adjust the position of the mirror holder until it is centered (Figure 2). For "spider-type" holders, this is usually done by turning the threaded rod that the secondary mirror mount is attached to. For single stalktype holders, you may have to bend the stalk to center the mirror. Refer to your telescope's manual for more specific instructions. Now you need to adjust the tilt of the secondary mirror so that the entire reflection of the primary mirror is precisely centered in the secondary mirror (and, thus, also on the crosshairs of the Collimating Eyepiece). [. . . ] To clean the eyepiece, use a blower bulb or a moist cotton swab to remove dirt from inside the barrel, and simply wipe the outside with a damp cloth. Make sure not to disturb the crosshairs, as bending or breaking may result. Your best bet is to store the Collimating Eyepiece in a case for easy access. If you drop the eyepiece, don't worry. [. . . ]