Calibration Access and Data Handbook
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The routine converts a corrected (flatfielded, background, deadtime)
count rate into magnitude values of the natural system by applying
the zero point correction.
The input count rate has already been corrected for instrumental effects
(as output from routine CAL_PhotoNatural
(see sect. 3.5.14) and for background contributions.
The definition of the zero point is retrieved from the extension COLORMAG
of the CCF component ColorTrans.
The zeropoints of the different filters are stored as real number
in the keywords ZPTFilterID:
ZPTU 
zero point of Ufilter 
ZPTB 
zero point of Bfilter 
ZPTV 
zero point of Vfilter 
ZPTUW1 
zero point of UW1filter 
ZPTUM2 
zero point of UM2filter 
ZPTUW2 
zero point of UW2filter 
ZPTMAGNI 
zero point of magnifier 
ZPTWHITE 
zero point of white lightfilter 
The count rates conversion is made with the assumption that the
full PSF is sampled. In case of partial PSF sampling the magnitudes
have to be corrected by the calling task.
The transformation of the input count rate
into the natural system (in units of magnitude)
is described by the equation:

(36) 
where is the zero point of the used filter.
The original routine has been aliased as CAL_omNaturalMagnitude.
Next: Calling Parameters
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Michael Smith
20110920