User's Guide to the Crossley Telescope

Table of Contents

Ground Level
Dome and Platform
Head Rotation
Dec Tangent Arm
Position Indicators
Mirror Cover
Dome Slit
Access Ports
RA Drive Preload
Operating Limits
New Telescope Drive

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The Telescope: Balance

The telescope should be balanced (or at least checked) by each observer at the beginning of his/her run. The balance should be checked with the RA and dec motions unclamped and all equipment (cold boxes and such) in position. Balance is checked by pushing and pulling the tube along the appropriate axes and judging if the force is equal or not in both directions. Proper balance is achieved when (1) it is balanced in the dec motion at the zenith, and at the equator it is balanced in (2) dec motion and (3) RA motion. If the telescope is not balanced properly, it will be necessary to adjust the weight distribution. There are photographs in the desk drawer in the office as well as in Figs. 75-77 of this manual which show approximate weight distributions for each instrument. You will often find that the dome crew has balanced the telescope satisfactorily, but balance is the responsibility of the observer.

Figure 75

Figure 76

Figure 77