Opened 16 years ago
#1359 new defect
CAL_PSF_MAG wrong, CAL_PSF_MAG_SIG undefined in SSdiff cmf files
| Reported by: | Michael Wood-Vasey | Owned by: | eugene |
|---|---|---|---|
| Priority: | normal | Milestone: | |
| Component: | psphot | Version: | |
| Severity: | normal | Keywords: | |
| Cc: |
Description
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.
