Orion SKYQUEST XX12 - Manual (Page 26)

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then remove any excess fluid with a fresh lens tissue. Oily fin-
gerprints 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 tis-
sue 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 flecks of paint
have virtually no adverse effect on the visual performance of
the telescope. The large primary mirror and the elliptical sec-
ondary mirror of your telescope are front surface aluminized
and over-coated with hard silicon dioxide, which prevents
the aluminum 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, you must carefully remove the mir-
ror cell from the telescope. To do this, remove the six screws
on the side of the tube near the rear end ring (see Figure
16). You do not need to remove the collimation screws on the
bottom of the mirror cell. Remove the entire mirror cell from
the tube. You will notice the primary mirror is held down with
three clips fastened by two screws each. Loosen the screws
and remove the clips. There are also three nylon-tipped set
screws which support and retain the mirror’s edge. These set
screws are located on the perimeter of the mirror cell. Use a
small flathead screwdriver to loosen each of these set screws
a few turns. You may now remove the mirror from the mirror
cell. Do not touch the surface of the mirror with your fingers;
lift it carefully by its edge.
Set the mirror, aluminized face up, on a clean, soft towel. Fill
a clean sink free of abrasive cleanser with room temperature
water, a few drops of liquid dishwashing detergent, and, if
possible, a capful of 100% isopropyl alcohol. Submerge the
mirror (aluminized face up) in the water and let it soak for a
few minutes (or hours if it’s a very dirty mirror). Wipe the mir-
ror under water with clean cotton balls, using extremely light
pressure and stroking in a straight line across the mirror. Use
one ball for each wipe across the mirror. Then rinse the mir-
ror under a stream of lukewarm water. Any particles on the
surface can be swabbed gently with a series of cotton balls,
each used just one time. Dry the mirror in a stream of air (a
“blower bulb” works great), or remove any stray drops of water
with the corner of a paper towel. Cover the mirror surface with
a tissue, and leave the mirror in a warm area until it is com-
pletely dry before reassembling the telescope. 7. specifications
optical tube assembly
Primary mirror:
305mm diameter reflective surface,
Pyrex, parabolic, center marked
Focal length: 1500mm
Focal ratio: f/4.9
Primary mirror cell: 9-point flotation, 3 spring-loaded
collimation knobs
Secondary mirror: 70mm minor axis, Pyrex
Secondary mirror
holder:
4-vaned spider assembly, 0.7mm thick
spider vanes, 3 SHCS for tilt adjustment
Mirror coatings: Aluminum with SiO2 overcoat
Focuser: Crayford, accepts 2" and 1.25"
eyepieces, 11:1 fine focus knob, all
metal construction
Optical tube
design:
Truss tube
Truss poles: 8 total (4 truss pole assembles with
2 poles each), 1.0" outer diameter,
aluminum black anodized, captive
assembly hardware
Navigation knob: Included
Optical tube
material:
Steel
Tube outer
diameter:
14.0"
OTA weight,
assembled:
49.5 lbs.
OTA weight,
disassembled:
Lower tube section weighs 34.3 lbs.,
upper tube section weighs 9.36 lbs.,
truss pole assemblies weigh 1.4 lbs.
each
OTA length,
assembled:
56"
OTA length,
disassembled:
Lower tube section is 26" long, upper
tube section is 8" long, truss pole
assemblies are 22" long