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: Head Rotation

The top 18" or so (the "head") of the telescope tube may be rotated 270 degrees clockwise and 90 degrees counterclockwise. There is a degree scale along the flange at the bottom of the rotating section and a bright metal index marker on the south side of the tube (Fig. 13). The "normal" orientation of the head of the telescope is with index marker at 270 degrees on the scale; that is, with the eyepieces south (tube east of the polar axle). Please faithfully return the head to exactly position angle 270 degrees at the conclusion of your run so as not to confuse the following observer. In order to turn the head, there is a locking lever inside the tube at the level of the degree scale, approximately a foot to the right of the eyepieces (Fig. 14). Left is locked, so turn the lever all the way to the right (clockwise) to unlock it and rotate the head to the desired position angle by hand. Relock by moving the lever all the way left.

Figure 13

Figure 14