Telescope Basics • 17
TELESCOPE BASICS
Once your telescope has been fully assembled, you are ready to attach the accesso-
ries and have a look. This section deals with basic telescope operations that are
common to all Celestron Schmidt-Cassegrain telescopes.
There are several accessories that come standard with all the Celestron Schmidt-
Cassegrain telescopes. The installation and use of each of these is described in this
section.
The Visual Back
The visual back is the accessory that allows you to attach all visual accessories to
the telescope. The G-9
1
/
4
comes with the visual back installed. If it is not already on
the tube it can be attached as follows:
1. Remove the rubber cover on the rear cell.
2. Place the knurled slip ring on the visual back over the threads on the rear cell
(see figure 3-2).
3. Hold the visual back with the set screw in a convenient position and rotate the
knurled slip ring clockwise until tight.
Once this is done, you are ready to attach other accessories, such as eyepieces,
diagonal prisms, etc.
If you want to remove the visual back, rotate the slip ring counterclockwise until it is
free of the rear cell.
The Star Diagonal
The star diagonal uses a mirror that reflects the light at a right angle to the light path
of the telescope. This allows you to observe in positions that are physically more
comfortable than if you were to look straight through. To attach the star diagonal:
1. Turn the set screw on the visual back until it no longer extends into (i.e., ob-
structs) its inner diameter of the visual back.
2. Slide the chrome portion of the star diagonal into the visual back (see figure 3-2).
3. Tighten the set screw to hold the star diagonal in place.
If you wish to change the orientation of the star diagonal, loosen the set screw on the
visual back until the star diagonal rotates freely. Rotate the diagonal to the desired
position and tighten the set screw.
Attaching the
Accessories
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