III. 4. C. Applying the transfomations

We next invoke "calib2.cl" to apply the transformations to the Mosaic *.als.2 files and average the results. The steps involved are as follows:

• First create a separate listing for each filter, using the FORTRAN program "sortfilt". This should produce <=40 files with names like "Uim1","Uim2". Some may not exist (as in the case that we only did photometry on a couple of chips).
• For each of the files that exists ("Bim1", say) run "total.cl" This generate a file (Bim1merge.dat) which contains the coordinates, average photometry, error, and number of frames the star was on.
• Run mkinvert.f This FORTRAN code does what "mkobsfile" and "invertfit" would do in photcal, transforming the photometry (chip-by-chip) into standard values. The outfiles files are "IM1.ubvri", "IM2.ubvri", etc.
• Run matchcheck.f to compare this transformed photometry to the 42-inch catalog. The program prints the median differences for the brighter stars (errors less than some amount), and also creates difference files "IMn.ubvridif" so we can ascertain if there are color trends.
• Run imtotal to produce a single catalog of all ubvri photometry (all chips). The output file is called "total.ubvri"
• Run matchcheckfin.f to compare "total.ubvri" to the 42-inch catalog.
• Run bigtotal.f to combine all the separate fields into one big catalog.