% @(#)bias_ccd.hlq	17.1.1.1 (ESO-SDAG) 01/25/02 17:48:52
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1993 European Southern Observatory
%.IDENT      bias_ccd.hlq
%.AUTHOR     RHW, IPG/ESO
%.KEYWORDS   MIDAS, ccd package, BIAS/CCD
%.PURPOSE    On-line help file for the command: BIAS/CCD
%.VERSION    930329 RHW created
%---------------------------------------------------------------------
\se
SECTION./CCD
\es\co
BIAS/CCD                                                        29-Mar-1993 RHW
\oc\su
BIAS/CCD [in_fram] [out_fram] [bs_fram]
	Correct the input frame for the bias offset using a bias frame
\us\pu
Purpose:    
	Correct the input frame for the bias offset using a bias frame
\up\sy
Syntax:     
	BIAS/CCD [in_fram] [out_fram] [bs_fram]
\ys\pa
	in_fram =  input frame to be corrected; No default.
\ap\pa
	out_fram = output frame resulting from subtracting the bias frame from
                   the input frame; no default.
\ap\pa
	bs_fram  = bias frame to be subtracted from input frame; default is 
                   the name stored in the keyword SC_BSFRM.
\ap\no
Note:       
	This command provides a simple subtraction of the bias offset from 
	a CCD frame. More advanced methods include fitting of the bias offset
	averaged over a number of rows or columns, and subtracting this fit
        result from all columns/rows of the science frame.\\

        In case the bias frame does not exit, a fatal error will be issued. In
        such case you may generate the bias frame using COMBINE/CCD.\\

        The command exits if the input frame has already been bias corrected.
	The descriptor CCDSTAT in the output frame is updated to indicated
	that the bias offset has been subtracted.
\on\see
See also:   
	SET/CCD, SHOW/CCD, REDUCE/CCD, OVERSCAN/CCD, COMBINE/CCD 
\ees\exs
Examples:
\ex
	BIAS/CCD susi0097 susi97bscor susibias
	Subtract the bias frame `susibias' from the input frame susi0097.
	The output frame is susi97bscor.
\xe \sxe