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: Is the telescope pointing out the slit?

The Crossley mounting often makes it difficult to tell if the telescope is being occulted by the edge of the dome slit. The safest way to assure yourself all is well is to go down and sight up the telescope tube from the bottom. If you do this a few times you will soon acquire confidence in your sense of where the telescope is pointing as seen from the top. Another way to tell is to sight out of the slit along an edge of one of the junction boxes at the top of the telescope, if that edge is itself parallel to the telescope tube. Since the telescope drives east to west, sight along a parallel edge on the east side of the tube and put the east side of the dome slit close to the tube. This gives you maximum clear slit to drive toward in case you get busy and forget to recenter the dome.