Data acquisition

The new Sequencer for NOTCam has been tested and will be offered to visitors on the next NOTCam observing run in May. A new sequencer version of the NOTCam script generator has been made, but needs testing. A number of scripts have already been converted to sequencer type, and a number of scripts still need to be written, also because the sequencer mode allows more scripting. All documentation will be updated to be Sequencer valid before the next visitor run in May.

The NOTCam teloffset command and the TCS autoguider status have been modified in order to avoid that an integration is started before the telescope has come completely at rest and is autoguiding after a dither. Whether more tweaking is needed must be tested in very good seeing. The modification does imply larger overheads when offsets are made.

The overheads related to data acquisition, being overheads to reading the array, storing the data files, and dithering the telescope, have been studied in a large dataset from 2006 to 2008 and a detailed report on the results was made. Surprisingly, the overheads change with time, and it appears to be important to monitor them. The reason why the dither overhead has increased is understood (see above). However, for the readout and storage overheads it is not at all clear what causes the sometimes very large overheads, and why they have become worse with time. Some possibilities have been suggested, but specific extra tests and a dedicated meeting are planned.