Celestron CGEM 1100 - Manual (Page 50)

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F F i i g g u u r r e e 8 8 - - 1 1
The three collimation screws are located
on the front of the secondary mirror
housing.
While your telescope requires little maintenance, there are a few things to remember that will ensure your telescope
performs at its best.
Care and Cleaning of the Optics
Occasionally, dust and/or moisture may build up on the corrector plate of your telescope. Special care should be
taken when cleaning any instrument so as not to damage the optics.
If dust has built up on the corrector plate, remove it with a brush (made of camel’s hair) or a can of pressurized air.
Spray at an angle to the lens for approximately two to four seconds. Then, use an optical cleaning solution and
white tissue paper to remove any remaining debris. Apply the solution to the tissue and then apply the tissue paper
to the lens. Low pressure strokes should go from the center of the corrector to the outer portion. Do NOT rub in
circles!
You can use a commercially made lens cleaner or mix your own. A good cleaning solution is isopropyl alcohol
mixed with distilled water. The solution should be 60% isopropyl alcohol and 40% distilled water. Or, liquid dish
soap diluted with water (a couple of drops per one quart of water) can be used.
Occasionally, you may experience dew build-up on the corrector plate of your telescope during an observing
session. If you want to continue observing, the dew must be removed, either with a hair dryer (on low setting) or by
pointing the telescope at the ground until the dew has evaporated.
If moisture condenses on the inside of the corrector, remove the accessories from the rear cell of the telescope.
Place the telescope in a dust-free environment and point it down. This will remove the moisture from the telescope
tube.
To minimize the need to clean your telescope, replace all lens covers once you have finished using it. Since the rear
cell is NOT sealed, the cover should be placed over the opening when not in use. This will prevent contaminants
from entering the optical tube.
Internal adjustments and cleaning should be done only by the Celestron repair department. If your telescope is in
need of internal cleaning, please call the factory for a return authorization number and price quote.
Collimation
The optical performance of your telescope is directly related to its collimation,
that is the alignment of its optical system. Your telescope was collimated at the
factory after it was completely assembled. However, if the telescope is dropped
or jarred severely during transport, it may have to be collimated. The only
optical element that may need to be adjusted, or is possible, is the tilt of the
secondary mirror.
To check the collimation of your telescope you will need a light source. A bright
star near the zenith is ideal since there is a minimal amount of atmospheric
distortion. Make sure that tracking is on so that you won’t have to manually track
the star. Or, if you do not want to power up your telescope, you can use Polaris.
Its position relative to the celestial pole means that it moves very little thus
eliminating the need to manually track it.