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Systemalfosc
Commandeasyflat
Arguments[-f] [<N>]
TypeDET
Short DescriptionMakes <N> automated imaging skyflats. If <N> is not specified, one skyflat will be done.
Long DescriptionA 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
  • 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
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.

If the -f flag is given, for fast mode, the prompt will be returned to the shell during the last readout.

Depends Onalfosc.abort alfosc.autosave_on alfosc.expose alfosc.imtype alfosc.object alfosc.resetxy alfosc.teloffset alfosc.xbeg alfosc.xbin alfosc.xsize alfosc.ybeg alfosc.ybin alfosc.ysize
Used In
Last Update0000-00-00 00:00:00
AuthorJHT
Back to top Last modified: February 14 2013