Observing system

Accompanying the change of detector controller there was also a change in the data acquisition system. In principle all the sequencer commands and script are the same as before, but they now command a different CCD control software. As part of the change the detector status display was upgraded. In general the change in the system has gone well, but some specific problems were encountered (see ``Main problems'' earlier given in this document).

One general issue that effects operation is the behaviour of the commands that effect the size and binning of the area of the CCD that is being readout. In particular, the specific order in which the commands are given determines the precise settings that are obtained. This is being corrected.

With the improved speed in readout time with the new detector controller there is an issue of having very many images in a single night. The naming convention we have been using is such that 4 digits are used and a maximum of 9999 images can be created with the same prefix for a given night. In one of the shortest nights this summer more than 4000 images were generated with the new controller when doing short cycle time-series observations where in a winter night one could have produced more than twice that number, making the generation of more than 9999 images in a night a real possibility. However, it was found that the new detector control software automatically switches to using 5 digits for the image number when reaching 10000 so there is no danger of overwriting existing data.