One interesting result with the new amplifiers is that it can be seen that the azimuth pre-load seems very small, which could be the reason for the jumps we have seen recorded in the log for this axis. In general, the telescope oscillations seems to have decreased, this can also be an effect of the azimuth and altitude tooth wheels being greased in November.

When differential tracking with autoguiding with a moving guide star box some warnings and display info have been added, especially of importance when the star box approaches an edge.

Tests with unguided tracking have been made with a differential speed of 600+ arcsec/hr, using star trails. They indicate that over a 600 sec exposure the telescope tracks at the specified rate, as determined from the total length of the trails, and any excursions in the trail are small. It is hard to quantify this in detail, but the precision in either of these measures is better than 1 arcsec.

Thomas Augusteijn 2009-05-14