id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
1359	CAL_PSF_MAG wrong, CAL_PSF_MAG_SIG undefined in SSdiff cmf files	Michael Wood-Vasey	eugene	"The CAL_PSF_MAG values are several magnitudes too faint and CAL_PSF_MAG_SIG is undefined in the recent SSdiff cmf files.  The CAL_PSF_MAG values range from 24.5-29 instead of from say 18-23. For example,

MD06.nightlyscience/2010/02/26/MD06/skycell.105/MD06.skycell.105.SS.dif.40577.cmf

A SNR of 5 is reported as CAL_PSF_MAG 28.4.  I would expect this to be close to 23.5.

This smacks of something like a missing factor of 2.5*log10(EXPTIME) in the zeropoint conversion.  But this isn't quite right.  This exptime in the FITS header says 1920 seconds and 2.5*log10(1920) is 8.2, and we're looking for something more like 5-6, but maybe my sense of what the values should be is slightly off and it is just 2.5*log10(EXPTIME).

Clearly CAL_PSF_MAG_SIG should probably just be PSF_INST_MAG_SIG, and we can use that for now; but this should be fixed as well."	defect	new	normal		psphot		normal