Rotator Issues when not at Zenith

Monday, January 14, 2013 2:18 PM

Problem(s) Encountered:

When the telescope was at hour angle -3 hours/7 minutes, with declination of +36 08, I attempted to rotate the instrument from -79 to -10 degrees.  When the instrument reached -37 degrees, it began to struggle and stopped rotating.  The rotator was still running, however the instrument failed to rotate past that angle.

This occurred at 3:07 am, and the temperature outside was 19 F.  When the telescope was put at zenith, the instrument rotated as if nothing was wrong.


There is a known issue with the rotator not working through the full travel range when the telescope is pointed at large angles.  This appears to have something to do with the torque associated with rotation of the friction-drive system for the rotator.  We check the friction drive tensioner from time to time in hopes that keeping it tight will mitigate this issue.