WHT slew speeds

The telescope slews to a new position on the sky at approximately 1 deg/sec in each of azimuth and elevation, with relatively short (few sec) overheads for acceleration and decleration.

The rotators on which the Cassegrain and prime-focus instruments are mounted also slew at approximately 1 deg/sec. The Cassegrain rotator decelerates slowly - total time for a rotation through theta deg is ~ theta + 30 sec.

The time taken to reach a new position is therefore often limited by the movement in azimuth, which can take up to ~ 5 min.

The azimuth, elevation and Cassegrain rotator speeds were last confirmed by Fiona Riddick in March 2016.