%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1994 European Southern Observatory
%.IDENT      skyexmos.hlq
%.AUTHOR     SM/LSW
%.KEYWORDS   MIDAS, help files, SKYEX/MOS
%.PURPOSE    On-line help file for the command: SKYEX/MOS
%.VERSION    1.0  4-AUG-1994 : Creation, SM
%----------------------------------------------------------------
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SECTION./MOS
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SKYEX/MOS					04-AUG-1994 SM
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SKYEX/MOS [object] [tabmos] [tabwin] [tabcoef] [skypar] [mode] [expar]
	fit sky for MOS, subtract it, extract and rebin objects
\us\pu
Purpose:   
	  Fit sky in a MOS image, subtract it, extract and rebin objects 
\up\sy	
Syntax:
	  SKYEX/MOS [object] [tabmos] [tabwin] [tabcoef] [skypar] [mode] [expar]
\ys\pa
	  object = object frame
              Session keyword: OBJECT
              Default value: none
	  tabmos = table with slitlet positions
              Session keyword: MOS
              Default value: mos
	  tabwin = table with windows positions
              Session keyword: WINDOWS
              Default value: window
	  tabcoef = table with dispersion coefficients
              Session keyword: LINFIT
              Default value: coerbr
	  skypar = parameters (not yet used)
              Session keyword: SKYPAR
              Default value: none
	  mode = method for fitting the sky background
              (0 =ignore table windows1=MEDIAN) 
              Session keyword: SKYMET
              Default value: none
	  expar = extraction parameters (order, number of iterations)
              Session keyword: EXTPAR
              Default value: none
\ap\sa
See also:
          SKYFIT/MOS, EXTRACT/MOS, REB1D/MOS
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Note:       
	  This command combines the SKYFIT/MOS, EXTRACT/MOS, and
	  REB1D/MOS. At first it fits the sky background in the
	  sky regions defined in tabwin.tbl, either by a polynoimal
	  fit or by taking the median over the defined background
	  region. The sky frame is named by adding the prefix SKY
	  to the name of the object frame. Then it subtracts the 
	  sky background and does an optimal extraction according 
	  to Horne's algorithm. The extracted frames are stored
	  as lines in a 2-dimensional frame, named by adding the
	  prefix EXT to the name of the input object frame.
	  The informations concerning the CCD parameters (gain, 
	  read-out-noise) and the rejection threshold are taken
	  from the keywords CCDPAR and REJTHRES, resp. 
	  Afterwards it rebins the one-dimensional spectra taking
	  start,end, and step from the keywords REBSTRT, REBEND,
	  and REBSTP. The names of the outframes are created by
	  adding the prefix REB to the original object's frame
	  name and adding the row number as suffix.
\on\exs
Examples:
\ex
          SKYFIT/MOS object mos windows coerbr ? 1 
          Determine the sky in the frame object.bdf. The limits of the slitlets
          are taken from the table mos and the windows for sky are defined
          in the table windows. The sky is approximated as the median value
          of all values marked as sky in table windows. The output is stored
          in frame SKYobject.bdf and subtracted from object.bdf (resulting in
          Sobject.bdf).
          It then extracts the objects as defined by windows.tbl (columns
          :Obj_Strt and :Obj_End). The extracted frames are stored in
          EXTobj.bdf. 
          Finally it takes the extracted spectra and rebins them, using
          the dispersion relation stored in coerbr.tbl and the rebinning
          parameters stored in REBMTD, REBSTRT, REBEND, and REBSTP. the
          rebinned frames are stored in files REBobject0001, REBobject0002, 
          etc.
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