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Cleaning telescope optics can be important but there are some
cautions that must be observed:
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Only clean optics if absolutely necessary. Do not clean
optics more often than needed.
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Be very careful not to scratch the optics. Dusty glass is
better than scratched glass.
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Use only the recommended materials for cleaning. Using other
cleaning supplies may damage the optics.
Follow the instruction below and everything should be fine. If you have
any questions, feel free to contact us
before proceeding and we will be happy to walk you through the process.
Cleaning Eyepieces
Eyepieces are the optical components that will need to be cleaned most often.
They are exposed to skin oils, gooey fingers ("Is this where I look?"), mascara,
and a host of other optical traumas. Fortunately, they are also the
easiest parts to clean.
What to Use
How to Do It
For eyepieces that are not too dirty, a
LensPen works great. The
LensPen has a brush on one end to clean off dust. Once the dust is
removed, the cleaning pad on the opposite end of the pen will remove smudges and
fingerprints.
If a more thorough cleaning job is required, begin by blowing off any dust
with a can of compressed air or use a soft brush. It is important to clean
dust off first, so that rubbing the glass does not scratch the coatings.
Apply a little alcohol to a 100% cotton ball. Do not soak the ball, just
get it damp. Run the ball once around the area of the top lens of the
eyepiece. Then, use a second, dry cotton ball to dry the lens. You
may have to repeat this sequence several times using new cotton balls each time.
Any remnant fuzzies from the cotton balls can be blown off with the air can or
brushed off.
Cleaning an SCT Corrector Lens
Cleaning the front corrector on an SCT is much more involved than cleaning
eyepieces, and care should be exercised at all times. Cleaning the
corrector should be done as infrequently as possible. Some dust on the
lens will have no effect on the views through the telescope. Once a year
or less often is all that should be necessary unless something traumatic happens
like a bird flying over and bombing your telescope.
Note: Distilled
water is safe to use on any optical surface. Manufacturers will recommend
using a mixture of water and isopropyl alcohol, but newer optical coatings may
be stained by the alcohol. Please
contact us for specific recommendations if you are unsure of the best
procedure for cleaning your telescope.
What to Use
How to Do It
1) Begin by pointing the nose of the telescope down at about a 45°
angle. This will allow the cleaning solution to run off the lens and not
into the telescope. Place a bucket or wastebasket under the corrector lens
to catch the liquid that runs off.
2) Use the compressed air can to blow of
as much dust as possible. Normally there will still be quite a bit of dust
remaining that the air cannot remove. This is fine.
3) Put the
distilled water into the
spray bottle.
4) Thoroughly spray the
distilled water
onto the corrector plate. Use a pretty liberal amount. This will
carry much of the dust off the lens.
5) Take a 100% cotton ball and roll it
once across the lens. This will pick up remaining dust rather than pushing
it across the lens and scratching the coatings. One cotton ball will only
cover a few inches of the lens. Throw the ball away and get a new one.
You will go through a lot of cotton balls, but they are a small price to pay to
keep the optics in top shape. Begin at the outside of the corrector and
work your way around and in toward the center.
6) Spray down the corrector again with the
distilled water.
7) This time, it is okay to wipe the
cotton balls across the surface of the lens. Wipe about 4-6 inches then
get a new cotton ball. Again, start outside and work in, continuing until
the whole lens is dry.
8) Leave the telescope pointed down to dry
for about half an hour. This will let the water that has leaked into
the gasket behind the corrector lens evaporate.
9) Once dry, blow off any remaining fuzzies from the cotton balls with the compressed air can.
Cleaning a Mirror
To clean a mirror, it normally must be removed from the telescope. This
will require collimating the system when it is reassembled. See the
Collimation page for details on doing this.
Cleaning a mirror should be done as infrequently as possible to prevent damage
to the coatings. A dusty mirror will not affect the view and is preferable
to a damaged one. Once a year or less often should be sufficient.
Use caution at all times while the mirror is out of the scope.
What to Use
How to Do It
1) Begin by removing the mirror cell from the telescope, then remove
the mirror from its cell. Place the mirror into an empty sink.
2) Blow off any loose dust with the compressed air. There will
typically be some dust that will not come off. This is fine.
3) Tip the mirror up at about a 45° angle. Slowly pour distilled water across the surface of the mirror to carry
away more dust.
4) Lay the mirror down flat and pour a small amount of water onto the
surface. The water should pool toward the center of the concave surface.
5) Take a 100% cotton ball and roll it
once across the mirror. This will pick up remaining dust rather than
pushing it across the mirror and scratching the coatings. One cotton ball
will only cover a few inches of the mirror. Throw the ball away and get a
new one. You will go through a lot of cotton balls, but they are a small
price to pay to keep the optics in top shape. Begin at the outside of the
mirror and work your way around and in toward the center.
6) Wet the mirror again.
7) This time, it is okay to wipe the
cotton balls across the surface of the mirror. Wipe about 4-6 inches then
get a new cotton ball. Again, start outside and work in, continuing until
the whole mirror is dry.
8) Leave the mirror to dry for a few
minutes
9) Once dry, blow off any remaining fuzzies from the cotton balls with the compressed air can.
Using a
Telescope
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