7
(ignore the dark reflection of the secondary mirror holder). If
it is not, adjust the three Phillips-head screws on the second-
ary mirror mount (you will need a Phillips screwdriver) until
the perimeter of the main mirror fits neatly within the outline
of the secondary mirror.
Now, the dark reflection of the secondary mirror holder in the
primary mirror will likely appear off-center, so you’ll need to
adjust the tilt of the primary mirror. This is done by adjusting
the three Phillips-head screws protruding from the back end of
the telescope. These are the collimation screws. Next to the
collimation screws you’ll see three other Phillips-head screws
whose heads are flat against the telescope. These screws
lock the mirror position and should be loosened a half turn or
so before adjusting the collimation screws. Turn any one of the
collimating screws no more than one-quarter turn at a time,
then recheck the mirror alignment. If it’s worse, turn the screw
in the opposite direction or try a different collimation screw. If
the screw is completely tight and will not turn further, loosen
the other two collimation screws. Loosening them too much
will move the main mirror too far forward, unbalancing the tel-
escope. Only a small adjustment should be needed! You
should be able to get the secondary mirror holder silhouette
centered in the reflection of the primary mirror, which you
already centered in the secondary mirror. When the adjust-
ment is complete, tighten the three mirror locking screws to fix
the primary mirror in position.
8. Care and Maintenance
Care of the Mount and Tube Assembly
Give your telescope reasonable care and it will last a lifetime.
Store it indoors or in a dry garage. Do not leave the telescope
outside except when using it. Keep it covered with a plastic
tarp or drop cloth to keep dust and dirt off. The optical tube is
aluminum and has a smooth painted surface that should
resist scratches and smudges. If a scratch does appear on
the tube, it will not harm the telescope. If you wish, you can
apply some white auto touch-up paint to the scratch.
Smudges can be wiped off with standard household cleaners
such as Windex or Formula 409.
Care of the Optics
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 finder
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. On larger lenses, clean only a small area at a time, using
a fresh lens tissue on each area. Never reuse tissues. Also, do
not take eyepieces apart to clean them.
Cleaning Mirrors
You should not have to clean your telescope’s mirrors very
often; normally once every few years. Covering your tele-
scope will prevent the mirrors from getting dirty. Improper
cleaning can scratch mirror coatings, so the fewer times you
have to clean the mirrors the better. Keep in mind that small
specks of dust or flecks of paint have virtually no effect on the
visual performance of the telescope.
The large primary mirror and the elliptical secondary mirror of
your telescope are front-surface aluminized and overcoated
with hard silicon monoxide, which prevents the aluminum
from oxidizing. These coatings normally last through many
years of use before requiring recoating (which is easily done).
The secondary mirror is more likely to require cleaning, because
it is right up near the eyepiece. First blow or brush the lens to
remove any dust (do not use canned compressed air as it con-
tains compounds harmful to first-surface mirrors), then clean the
mirror surface with ordinary lens fluid and cleaning tissue. Be
extra gentle so as not to rub grit into the coating. (Very tiny, bare-
ly visible “sleeks” are not unusual and do not affect
performance.)
To clean the primary mirror, carefully remove the mirror cell from
the telescope. Do not attempt to remove the mirror from the
cell—it has been secured in place by both clamps and adhe-
sive. Be careful not to touch the front surface of the mirror with
your fingers! Set the mirror 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 rubbing alcohol. Submerge the mirror (aluminized face
up) in the water and let it soak for several minutes (or hours if
it’s a very dirty mirror). Wipe the mirror under water 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. Then rinse the mirror under a stream of luke-
warm water. Any particles on the surface can be swabbed
gently with a series of clean cotton balls, each used just one
time. Dry the mirror in a stream of air (a “blower bulb” works
great), and remove any stray drops of water with the corner of
a paper towel. Water will run off a clean surface. Dry the cell and
exposed surfaces with a towel. Cover the mirror surface with
Kleenex, and leave the entire assembly in a warm area until it
is completely dry before reassembling the telescope.
9. Specifications
Primary mirror: 3" (76mm) diameter, aluminized and over-
coated with silicon monoxide
Focal length: 700mm
Focal ratio: f/9.2
Magnification: 35x with 20mm eyepiece
Finder scope: 5x magnification, achromatic
Eyepiece: 20mm Kellner, fully coated
