Subtracting the Overscan using IRAF

Since the MAESTRO CCD is read out with two amps, there are two overscan regions. However, the file produced by ICE/IRAF is a fits file which is not multi-dimensional. So we have written a script to subtract the overscan region for each half of the image, and produce a single,
trimmed fits file without the overscan. We then edit header information so that ccdproc subsequently can be run.

The cl is called "maestro_biaser.cl"

Currently it only runs on 1x1 binned data.

# Maestro de-overscanner version of 21 July 2007
# written by Ed Olszewski, Jill Bechtold and Christy Tremonti
# THIS DESTROYS THE ORIGINAL COPY OF THE IMAGE, so make copies in a REDUCED AREA
# The values for binning 1x1 are hardwired in at this time
#
# so to run this, in iraf you say "task maestro_biaser = maestro_biaser.cl"
# then you say "maestro_biaser filename.fits" or just "maestro_biaser"
# you can also say "epar maestro_biaser"
#
# You can use the usual iraf lists
#
# it works by making two temporary copies of the file to be de-overscanned
# and doing ccdproc and trimming on each amp in turn
# then copying the two halves onto a 4096x4096 image
# at the end, it cleans up and fools iraf into thinking it did
# the work itself
# so, flatfielding etc ought to work in iraf as usual

need to make it do binned data

• maestro_biaser.cl: maestro_biaser.cl version july 2007
• maestro_biaser.cl: IRAF script to subtract overscan for MAESTRO format files <-- LATEST VERSION, Dec. 12, 2007