# Units:
#  "lambda" is in Angstroms
#  "pass" is the contribution to the detector signal per photon
#         entering the atmosphere of Earth (for airmass 1.3)
#  "pass_1_[069]" are the contribution to the signal for airmasses
#         1.0, 1.6, and 1.9 respectively
#
# Bandpass Name(s): [SPECIFY]
#
# Instrument: SDSS telescope at APO [SPECIFY: WHICH COLUMN]
# 
# Determined by: Jim Gunn, Mamoru Doi, Daniel Eisenstein
#
# Date of determination: 2001-12-18
#
# Meaning of/Reason for default column: 1.3 airmass; SDSS magnitudes are
#   calibrated to this airmass
#
# Notes:
#
#  Keep in mind that SDSS pipelines are output in the MAYBE magnitude 
#  system, which is currently (2002-08-19) thought to be related to
#  the AB magnitude system by the offsets:
#
#    u(AB,2.5m) = u(MAYBE,2.5m) - 0.042
#    g(AB,2.5m) = g(MAYBE,2.5m) + 0.036
#    r(AB,2.5m) = r(MAYBE,2.5m) + 0.015
#    i(AB,2.5m) = i(MAYBE,2.5m) + 0.013
#    z(AB,2.5m) = z(MAYBE,2.5m) - 0.002
#
#  See sdss-general/2486 or contact David W. Hogg for details.
#
#  The following notes come from Jim Gunn:
# 
#    These files are the response functions as measured by Mamoru Jan 2001,
#    interpolated to fill in the sharp corner near the red cutoff using model
#    filters and then splined to a standard wavelengh set, shared by all of
#    the files in this set of response functions for all the telescopes.
#  
#    The files indexed 0 are the response functions averaged over the six
#    columns of the camera.
#    
#    The file sdssav.lis is a list of magnitudes (V=0) and colors for these
#    (average) response functions at 1.3 airmasses run against the
#    Gunn-Stryker spectrophotometric atlas stars and the AB95 standards. 
#    These are AB magnitudes, note, not whatever system we will come up with. 
#    To transform from USNO magnitudes to a natural SDSS AB system, the
#    best-guess transformations as of this writing are
#  
#    u_AB = u' - 0.04 - 0.003*(u'-g')
#    
#    g_AB = g'        + 0.069*(g'-r') 
#    
#    r_AB = r'        + 0.038*(r'-i') 
#    
#    i_AB = i'        + 0.049*(r'-i')
#    
#    z_AB = z' - 0.01 + 0.011*(i'-z')
#    
#    but these are based ENTIRELY on calculations, and should be much better
#    determined by observations shortly.
#    
#    jeg011218
#