Celestron OMNI XLT 102 Telescope User Manual


 
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While your telescope requires little maintenance, there are a few things to remember that will ensure your telescope
performs at its best. Each optical design type has special collimation instructions described below.
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Occasionally dust and/or moisture may build up on the objective lens, the corrector plate, or primary mirror
depending on which type of telescope you have. Special care should be taken when cleaning any instrument so as
not to damage the optics.
If dust has built up on the optics, remove it with a brush (made of camel’s hair) or a can of pressurized air (spray at
an angle to the glass surface 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 optics. Low pressure strokes should go from the center of the lens (or mirror) 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 optics 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 optics, remove the accessories from 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 cells
are NOT sealed, the covers should be placed over the openings 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 information.
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Be sure to completely read carefully before attempting collimation.
Collimation is the process of aligning the optical axis of each optical
element with each other and with the mechanical axis of the
telescope tube. For a refractor telescope design this means aligning
the optical axis of the objective lens with the optical axis of the
eyepiece on the other end of the tube. Your Omni refractor was
properly aligned at the factory. However, extremely rough handling
while traveling may eventually alter the alignment of the lens. Your
Omni refractor telescope may come with an adjustable objective lens
housing to assist in the alignment of the optical axis. It is rare that
collimation would be necessary and if your telescope does not have
collimation adjustment screws, you may have to send it to the factory
for alignment.
To determine whether or not re-collimation is necessary the
telescope should be set up outside at night. It should be a still night
and one in which you have let the telescope sit outside for 15 to 30
minutes before attempting collimation. You should also wait for a
night with good seeing conditions and avoid looking over anything
that produces heat waves (i.e., roof tops, car hoods, etc.).
Mounting Screws
(Phillips head)
Collimation
Screws
(Allen head)
Figure 7-1
Objective lens housing (with lens shade removed)
show mounting and collimation screws.