Imaging

Since the commissioning of the new science grade array some more experience with this new detector has been gained and it has become evident that the use of differential sky-flats to make master flats does not work as well as with the previous arrays because the remnants of the reset ramp is now visible in the master flat. A closer look at the data taken with the engineering grade array when testing the new PCB shows that the new PCB introduces a stronger and more persistent ``reset anomaly''. The consequence of this is that the method of obtaining flat fields must be revised. Dome flats taken with multiple reads do get rid of the reset ramp, but multiple reads require a minimum exposure time of $\sim$20 seconds, which is too much for differential twilight flats since the useful twilight slot is limited. Investigations are currently being made on the quality of such dome-flats and on the recommendations for NOTCam calibrations and data reductions.

The imaging quality control (basically sky level and zero-point monitoring) is still handled on a manual level only. The script which reduces the standard star images, makes the photometry and feeds the result into the database needs to be finished.