PROMPT processing pipeline:

noao.obsutil.findgain
FINDGAIN:
  center = mean, binwidth = 0.1
  nclip = 3, lsigma = 4., usigma = 4.

  Flats      = FLAT_Prompt5_06_13_08_113706_V_051  &  FLAT_Prompt5_06_13_08_113706_V_060
  Zeros      = DARK_Prompt5_06_15_08_114980__001  &  DARK_Prompt5_06_15_08_114980__020
  Gain       =  1.36 electrons per ADU
  Read noise =  9.39 electrons

From Joshua Haislip:

Readnoise: 6.6 ADU (9.2 e-)
Gain: 1.4 e-/ADU 

calibration
-----------

imstat images to make sure there's nothing unusual

Make the following list files:
biaslist - list of bias images
zerolist - list of images to be bias corrected (dark, flat and object images)
darklist - list of dark image files
undarklist - list of images to be dark corrected (flat and object images)
flatVlist - list of Vflat field images
flatIlist - list of Iflat field images
objVlist - list of V object images to be flat field corrected
objIlist - list of I object images to be flat field corrected

Then run prcal.cl