[Comm2011] observed vs ETC-predicted #electrons

[Gijs Verdoes Kleijn]

Dear all,

I compared observed counts in e- vs ETC-predicted ones for only 4 stars 
in standard star fields in g and r:

         #OCAM1B:
         #gain e-/ADU  2.1424541471
         #filter  OCAM_g_SDSS
         #airmass 1.106
         #EXPTIME 60.0
         #PSF (FWHM,arcsec) 0.525361080408
         #DATE-OBS 2011-05-02 09:05:51
         #chip  ESO_CCD_#88
         #observed counts (e-) ETC-predicted (e-)
         # 52779 124405
         # 9651 26225

         #OCAM1A:
         #DATE-OBS 2011-03-28 04:07:09
         #chip  ESO_CCD_#96
         #gain e-/ADU  2.03434382233
         #filter  OCAM_r_SDSS
         #airmass 1.128
         #EXPTIME 10.0
         #PSF 1.00567699718
         #observed counts (e-) vs ETC-predicted (e-)
         # 28405 vs 23536
         # 218067 vs 205054

         #OCAM1A
          #DATE-OBS 2011-03-28 04:05:21
         #chip  ESO_CCD_#75
         #gain e-/ADU  2.16366010563
         #filter  OCAM_g_SDSS
         #airmass 1.131
         #EXPTIME 10.0
         #PSF 0.58974484992
         #observed counts (e-) vs ETC-predicted (e-)
         #6280 9542
         #61328 69328
         #36645 42044

First impression:
factor ~2.5 less e-s observed than predicted for g in OCAM1B observation
good agreement for r, and ~25% agreement for g observations in OCAM1A.

Needs more checks before I want to trust these first quick calculations.
To be continued.

Cheers, Gijs