|Long Description||A script to do <N> imaging skyflats. If the argument is not given, it will only do one skyflat. Takes a small unbinned Y-windowed flat image, finds median value and bias level (using qc-user@elena:alfosc/skyflats/alfoscskycounts.py), sets back the original window/binning and fires off an exposure aiming for 100 kADU. If the test-image count rate is too high or too low, then the script either retries the test image after 20 seconds, or exits (depending on morning or evening). Once a real flat-field image is taken, this and any subsequent flat-field images are also analysed, and the next exposure time is computed accordingly. The exposure-time algorithm is based on the requirements |
When the sky is dark, and the counts aimed-for cannot be reached within 300 seconds, the script will still take a 300s flat if the expected counts are above the minimum acceptable count level (30 kADU). Similarly, for bright sky, a 1-second flat will be taken if the counts will be below the maximal count level of 250 kADU. Does a teloffset after each flat during readout, in a spiraling sequence, with a grid spacing of 15 arcsec. Does not do any instrument setup. Switches on autosave, and leaves it on. Switches on remsave (to /data/service/calib/), and switches it off at exit. Does not alter amplifier settings. Note: polarimetry flats will only work with polwin.
- the minimum exposure time is 1 second
- the maximal exposure time is 300 seconds
- the minimum count level is 30 kADU
- the maximal count level is 250 kADU
- the aim is 100 kADU
If the -f flag is given, for fast mode, the prompt will be returned to the shell during the last readout.