The FPGEN module (“Final Product Generator”) updates the FITS header keywords of bcd.fits to make them more human readable. It does the following: (1) modifies comments in the comments field of individual keywords, (2) reorders keywords, (3) renames keywords, and (4) adds new keywords with information from the database. The following are examples of this processing:
-In the header keyword, INSTRUME= ’IRSX ’, the comment field "/ Spitzer Space Telescope instrument ID" is deleted by FPGEN.
-The header keywords APERTURE and APERNAME are renamed to FOVID and FOVNAME.
-The keywords PKUPRA (RA peakup position in degrees) and PKUPDEC (Dec peakup position in degrees) are read from the database.
Many header keywords are simply “passed through” (copied directly) from the original bcd.fits header. These keywords may be re-ordered by FPGEN. Examples of keywords that are passed through are those for World Coordinate System (WCS) information; see Section 5.4 on the Peak-Up Cut-Outs pipeline.
The HDRUPD8 (“Header Update, version 8”) module adds or deletes header keywords from a bcd.fits file. The text of the header lines to be added or deleted is contained in a file that is passed to HDRUPD8. This module operates in conjunction with FPGEN.