Basic Imaging Data Processing

Copy over the science datafiles. In this example the filenames all begin with EGS, but that is not generally the case.

me> cp /data/mega1/Archive/rawdata/data/ARCHMEGACAM/2005.0605/EGS*.fits .

Overscan correct, trim, and zero-subtract the science data using the Zero.fits file and the twilight flat just generated. One command will handle multiple bands:

me> ccdproc EGS*.fits overscan+ trim+ zerocor+ zero="Zero.fits" flatcor+ flat="Flat?.fits"

Fix bad pixels (this must be done after trimming!) First add pointers to all the bad pixel files These masks are appropriate only for binx2 data. Note: The bad pixel masks miss a lot of bad columns and pixels. see /data/irac9/mashby/deep_survey/megacam/2005.12.new/fix_bpm.macro, which is itself only appropriate for megamerged data, for more bad columns than are documented in the megacam$Badpix/ directory as of December 2005. For their use on megamerged data, see far below.

me> addbpm EGS*.fits bpmaskdir = "megacam$Badpix/"
me> ccdproc EGS*.fits fixpix+

If your data were acquired prior to 2008 June, you'll have to adjust the rotation angle by -0.5 degrees. The rotation encoder had been off by 0.5 degrees on the telescope, but by 2008 June that was fixed.

me> fixmosaic EGS*.fits fixmos- fixrot+ fixcen- fix0704- rotcorr=-0.5

Now you're ready to move on to the next phase (sky/fringe subtraction).

Last updated July 12, 2008.