% @(#)illumiccd.hlq	17.1.1.1 (ESO-SDAG) 01/25/02 17:48:54
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1993 European Southern Observatory
%.IDENT      illumiccd.hlq
%.AUTHOR     RHW, IPG/ESO
%.KEYWORDS   MIDAS, ccd package, ILLUMINATION/CCD
%.PURPOSE    On-line help file for the command: ILLUMINATION/CCD
%.VERSION    930827 RHW created
%---------------------------------------------------------------------
\se
SECTION./CCD
\es\co
ILLUMINATION/CCD                                                27-August-1993
\oc\su
ILLUMINATION/CCD [in_fram] [out_fram] [il_fram]
	Do an illumination correction of the input frame
\us\pu
Purpose:    
	Do an illumination correction of the input frame
\up\sy
Syntax:     
	ILLUMINATION/CCD [in_fram] [out_fram] [il_fram]
\ys\pa
	in_fram =  input frame to be corrected; default is the frame stored in
                   the keyword CCD_IN.
\ap\pa
	out_fram = output frame resulting from the devision of the input frame
                   by a scaled illumination field; no default.
\ap\pa
	il_fram  = illumination frame by which input frame is to be divided;
                   default is the frame stored in the keyword SC_ILFRM.
\ap\no
Note:   
        The command devides the input frame by the flat field frame according
        to the formula:\\
                       out_fram = in_fram*mean/il_fram\\
        where mean is the value of the descriptor `CCDMEAN' in the illumination
        frame, created when the illumination frame produced. Its value is 
        computed over the useful image defined in the keyword 'IM_SEC'. In 
        case the descriptor does not exist, the mean intensity over the 
        ilumination frame using the area in the key `IM_SEC' will be used as 
        the scaling factor. In case the descriptor contains a number smaller 
        or equal to zero the value 1.0 will be used.\\

        In case the illumination frame does not exit or the frame cannot be 
        used as an illumination frame a fatal error will be issued.\\

        The command exists if the illumination correction was already applied.
	After the command has finished the descriptor CCDSTAT in the output 
        frame is updated to indicated that the frame is illumination corrected.
\on\see
See also:   
	SET/CCD, SHOW/CCD, REDUCE/CCD, ILLCOR/CCD, ILLFLAT/CCD, SKYCOR/CCD, 
        SKYFLAT/CCD
\ees\exs
Examples:
\ex
	ILLUM/CCD susi0097dkcor susi97ilcor susi0097_il
	Devide susu0097dkcor by the scale illumination correction frame 
        susi0097_il. The output frame is susi97ilcor.
\xe \sxe