acm_ccd_fixup
Updated: Sep22,2018

Correct problems with acm images written with PAS.

  1. A basic run.
  2. What is up with the bias overscan region?


A basic run.

The PAS headers and the general properties of acm images from PAS can change with the wind. To recover an image that will work with my downstream codes I use this routine to perform various fixes: 


% acm_ccd_fixup list.0 N 
arg1 - Name of file listing input acm images (can be full path)
arg2 - Run in verboxe mode (Y/N)

The most up-to-date documentation is available with: 
% acm_ccd_fixup --help  

IMPORTANT NOTE: The product images are deposited in:   ./local_red/FIXUP 

Some important points: 
 1) The list of header cards to be removed is taken from $critfils/ACM/bad.cards 
 2) If no local fbp.fits file exists, then one is retrieved from $critfils/ACM/acm_FBP_MEAN.fits
Recall that "fbp" denotes "fixed bias pattern". The acm has a very significant fbp, and removing it with even an old archived file is a useful step.



What is up with bias overscan region?.

In early summer 2018 a piece of code was added to PAS to create a bias ovescan area in the acm images. This never worked and has yet (as of Sep2018) to be corrected. Should this be fixed in the future, acm_ccd_fixup will be adjusted to subtract the bias using the bias overscan. For now, all that is subtracted is a fixed bias pattern that resides in $critfils/ACM/acm_FBP_MEAN.fits. In the future I may provide a way of using a local fixed bias pattern file that could be constructed from nightly data. This should significantly improve the quality of this correction.



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