Telescope parts: Moving the dome in azimuth and zenith angle

Azimuth motion:

• The azimuth arm can rotate 0-720 degrees. Maximum rate is .4167 deg/sec (25 deg/min).  Max acceleration is .1 deg/sec^2.
• It rides on two circular rails (inner and outer rails). There are  32 wheels each supporting about 16 tons. 8 of the wheels are driven by electric motors.
• An encoder rack gear is mounted on the inside of the ring girder. An encoder rides in this gear and is used to determine the azimuth position (resolution .0001 deg).

• The dome can move 1.06 to 19.69 deg in za. Maximum rate is .0417 deg/sec (2.5 deg/min). Max acceleration is .025 deg/sec^2.
• It rides on two rails. There are 32 wheels each supporting about 3.4 tons. The dome is pulled uphill/downhill by 8 electric motors that drive on a rack gear (centered between the two support rails).
• An encoder rides on the rack gear and measures the zenith angle (resolution .0001 deg).
• A hydraulic brake system provides resistance as the dome moves downhill. If we have a motor failure, the dome will stop before it reaches 4 degrees za.