SIRTF IRAC Test Data, Cosmic Ray Data

 Cosmic Ray map
  - SSC criteria:  >5 sigma above local bkg
    0 = OK
    1 = CR hit 

Our calibrated images already have cosmic ray hits in them, different for Visit 1 
and Visit 2 since they are from different WFPC2 images. 
Our cosmic ray mask was created by running the IDL routine "sigma_filter" on the 
calibrated image, with N_sigma=5 as a parameter. This created a new image with the
cosmic ray pixels "fixed".  We then found the pixels that were different 
between the calibrated image and the "fixed" calibrated image and those pixels were
assigned a value of "1" in the cosmic ray mask.