Orion 9791 instruction manual Care and Maintenance, Cleaning Eyepiece Lenses, Cleaning Mirrors

a.

Metal washer

Small plastic
washer	Plastic washer
(not visible)

b.

Figure 50. (a) The primary mirror is held in its cell with three hex head retaining bolts. (b) Between each bolt head and the mirror surface are two washers, a metal washer and a plastic washer, which is the one that actually contacts the mirror surface. A third, smaller washer rests directly on top of the threaded post that the retaining bolt screws into.

Note About Astro-imaging

The SkyQuest XX14i IntelliScope Truss Tube Dobsonian is designed for visual, not imaging, use. The Dobsonian mount is not an equatorial-type mount, and is not motor driven for long exposure astro-imaging. The telescope has also been optically optimized for visual use, since photographic optimi- zation degrades visual performance.

With that in mind, however, it is possible to do some simple astro-imaging with the XX14i. With the use of afocal imaging techniques (where the camera is simply held to the eyepiece to take a picture) and digital cameras, it is possible to capture images of bright objects. Certain imaging accessories, such as the Orion SteadyPix, can help in obtaining images by the afocal method.

6. Care and Maintenance

If you give your telescope reasonable care, it will last a life- time. Store it in a clean, dry, dust-free place, safe from rapid changes in temperature and humidity. Do not store the tele- scope outdoors, although storage in a garage or shed is okay. The telescope can be stored assembled or disassembled, but be sure to keep the dust covers on the telescope when not in use. We highly recommend storing the optical tube sec- tions in the optional case set for the XX14i. Small components like eyepieces and other accessories should be kept in an optional accessory case.

Your XX14i requires very little mechanical maintenance. The optical tube is steel and has a painted finish that is fairly scratch-resistant. If a scratch does appear on the tube, it will not harm the telescope. Smudges on the tube or base can be wiped off with a soft cloth and household cleaning fluid.

Cleaning Eyepiece Lenses

Any quality optical lens cleaning tissue and optical lens clean- ing fluid specifically designed for multi-coated optics can be used to clean the exposed lenses of your eyepieces or find- er scope. Never use regular glass cleaner or cleaning fluid

designed for eyeglasses. Before cleaning with fluid and tissue, however, blow any loose particles off the lens with a blower bulb or compressed air. Then apply some cleaning fluid to a tissue, never directly on the optics. Wipe the lens gently in a circular motion, then remove any excess fluid with a fresh lens tissue. Oily fingerprints and smudges may be removed using this method. Use caution; rubbing too hard may scratch the lens. For larger lenses, clean only a small area at a time using a fresh lens tissue on each area. Never reuse cleaning tissues.

Cleaning Mirrors

You should not have to clean the telescope’s mirrors very often; normally once every few years or so. Covering the tele- scope with the dust covers when it is not in use will prevent dust from accumulating on the mirrors. Improper cleaning can scratch mirror coatings, so the fewer times you have to clean the mirrors, the better. Small specks of dust or debris have virtually no adverse effect on the visual performance of the telescope. The large primary mirror and the elliptical second- ary mirror of your telescope are front surface aluminized and over-coated with hard silicon dioxide, which prevents the alu- minum from oxidizing. These coatings normally last through many years of use before requiring re-coating.

To clean the secondary mirror, you will need to remove it from the telescope. Before doing so, remove the upper tube section from the assembled telescope. Hold the secondary mirror sta- tionary while loosening the center Phillips-head screw. Handle the mirror by its edge; avoid touching the mirror surface itself. Once the mirror (still in its holder) is removed from the tube, follow the same procedure described below for cleaning the primary mirror. You do not need to remove the secondary mir- ror from its holder when cleaning.

To clean the primary mirror, first remove the rear end ring and mirror cell from the lower tube section (Figure 50a). Loosen the three hex head retaining bolts and carefully remove them along with the two washers between the bolt head and mirror surface (Figure 50b) and set them aside. You’ll notice that there is a third, smaller washer underneath the large plastic

31