Specifications - Orion StarBlast Instruction Manual

Cleaning Mirrors
You should not have to clean the telescope's mirrors very often;
normally once every year or so is fine. Covering the front open-
ing of the telescope with the dust cover when it is not in use
will prevent dust from accumulating on the mirrors. Keeping
the dust cap on the focuser's 1.25" opening is also a good
idea. Improper cleaning can scratch the 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 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 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, first remove it from the telescope.
Do this by keeping the secondary mirror holder stationary while
completely unthreading the Phillips-head screw in the center
hub of the spider vane assembly (see Figure 5). Do not touch
the mirror surface when doing this. Be careful, there is a spring
between the secondary mirror holder and the Phillips head
screw; be sure it does not fall into the optical tube and onto the
primary mirror. Once the Phillips-head screw is unthreaded,
the secondary mirror and its holder can be removed from the
telescope. Then follow the same procedure described below
for cleaning the primary mirror. The secondary mirror does not
need to be removed from its holder for cleaning.
To clean the primary mirror, first carefully remove the mirror
cell from the telescope. For the StarBlast, you must completely
unthread the three screws on the exterior perimeter of the mir-
ror cell (Figure 10). Then pull the cell away from the tube. You
will notice the primary mirror is held in the mirror cell with three
clips held by two screws each. Loosen the screws and remove
the clips.
Small Phillips-head screws (3)
Figure 10.
To remove the mirror cell from the telescope, the
three small Phillips-head screws on the perimeter of the mirror cell
must be completely unthreaded.
You may now remove the primary mirror from its cell. Do not
touch the surface of the mirror with your fingers. Lift the mirror
carefully by the edges. Set the mirror on a clean soft towel. Fill
a clean sink free with room temperature water, a few drops
of liquid dishwashing detergent, and if possible, a capfull 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 mirror under water with
clean cotton balls, using extremely light pressure and strok-
ing in straight lines across the mirror surface. Use one ball
for each wipe across the mirror. Then rinse the mirror 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 surface with a stream of air (a "blower
bulb" works great). Cover the mirror surface with tissue, and
leave the mirror in a warm area until it is completely dry before
replacing it in the mirror cell and telescope.

specifications

Optical tube:
Primary mirror:
Aperture:
Effective focal length:
Focal ratio:
Minor axis of secondary mirror:
Mirror coatings:
Focuser:
Weight:
Length:
Steel
Parabolic, center marked
4.5" (114mm)
450mm
f/3.9
1.85" (47.0mm)
Aluminum with silocon
dioxide (SiO ) overcoat
2
Rack-and-pinion, accepts
1.25" eyepieces
3.7 lbs.
17.25"
7