Use data from a run of ds9_imstats (in the *.info file) to install a variety of useful values in the FITS header of the input image.

% acm_skysb_stats --help 
Usage: acm_skysb_stats 20180206T022042.6_acm_sci_proc.fits Y N
arg1 - Name of LOCAL FITS image with table file to be analysed 
arg2 - install SKYSB stats into header (Y/N)
arg3 - run in debug mode (Y/N)

% acm_skysb_stats 20180403T042947.5_acm_sci_proc.fits Y N  

This may change, but here are the header cards installed as of Jun2018 
SKYSB   = '17.82975'     # Measured sky surface brightness in mags per sq.arcsec
SKYSBERR= '0.003850'     # mean error in SKYSB 
RSTRT   = '279.7965'     # Combined offset of tracker (X_STRT,Y_STRT in quadrature) 
MILLUM  = '97.300  '     # Percentage moon illumination, 100% at full moon 
PHIMOON = '32.597095'    # Moon sparation angle (degrees) 
VSKYSB  = '17.044998'    # Predicted V sky surface brightness (mss)