23
7. MAINTENANCE
For faultless operation the telescope should be kept in cleanness
and protected against mechanical damage. The metal surfaces are
periodically dusted by using clean soft napkins, then wiped with
a napkin impregnated with acidless vaseline, after that with a dry
napkin.
The aluminized mirrors require particular care. The accumulated
dust is removed only with the use of a soft brush or cotton wool tampon.
Cleaning should be carried out without excessive effort to avoid formation
of thin scratches on the mirrors surface which deteriorate the image.
If some fat spots are found on the mirrors, never wipe them. In this
case the mirrors are washed. The primary mirror (fig. 2) is taken out
of the tube after unscrewing the screws which fix the cell to the tube.
Without removing the mirror from the cell, the mirror surface is wetted
considerably with pure medical alcohol with the help of a cotton wool
tampon. By using the same tampon, one wipes slightly the wet mirror
without excessive effort and puts it at once under the stream of pure water.
After removing alcohol in this way, one puts the mirror on its edge until
it is dried. The drops of water are removed with a blotter by slight
touching them with a blotter corner.
The diagonal mirror is cleaned in the same way. After cleaning the
mirrors are put in their places.
Tile lenses of the eyepieces are wiped with a dry linen napkin. The
fat spots are removed with a cotton wool piece impregnated with
alcohol.
One should dismantle the optics only in case of necessity.
In non-
operating position the telescope tube must be constantly covered with
a cap and the eyepiece one is to be plugged with a stopper.
