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 objective lens 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 al-
cohol 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 ses-
sion. 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 tele-
scope 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 tele-
scope is in need of internal cleaning, please call the factory for a return authorization number and price
quote.
COLLIMATION OF A NEWTONIAN
The optical performance of most Newtonian reflecting telescopes can be optimized by re-collimating (align-
ing) the telescope’s optics, as needed. To collimate the telescope simply means to bring its optical elements
into balance. Poor collimation will result in optical aberrations and distortions.
Before collimating your telescope, take time to familiarize yourself with all its components. The primary
mirror is the large mirror at the back end of the telescope tube. This mirror is adjusted by loosening and
tightening the three screws, placed 120 degrees apart, at the end of the telescope tube. The secondary mir-
ror (the small, elliptical mirror under the focuser, in the front of the tube) also has three adjustment screws
(you will need optional tools (described below) to perform collimation. To determine if your telescope
needs collimation first point your telescope toward a bright wall or blue sky outside.
20
TELESCOPE MAINTENANCE
