% @(#)disperhoug.hlq	17.1.1.1 (ESO-IPG) 01/25/02 17:55:39
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%.COPYRIGHT  (c)  1993 European Southern Observatory
%.IDENT      disperhoug.hlq
%.AUTHOR     PB, IPG/ESO
%.KEYWORDS   MIDAS, help files, 
%.PURPOSE    On-line help file for the command: DISPERSION/HOUGH
%.VERSION    1.0  22-MAR-95 : Creation, PB
%----------------------------------------------------------------
\se
SECTION./HOUGH
\es\co
DISPERSION/HOUGH				    22-MAR-95  PB
\oc\su
DISPERS/HOUGH [wdisp] [wcent] fr_specs [line] [cat] [mode] [range] [vflag]
	Determination of dispersion relations by HT
\us\pu
Purpose:    
            This low-level command is used in the Long and Echelle packages
            to determine dispersion relations by Hough transform. A number 
            of default keywords (AVDISP, WCENTER, LINTAB, LINCAT) are
            supposed to exist in the calling package.
\up\sy
Syntax:     
            DISP/HOUGH [wdisp] [wcent] fr_sp [line] [cat] [mode] [range] [vfl]
\ys\pa
            wdisp  = Average dispersion, defaulted to session keyword \\
                     AVDISP.
\ap\pa
            wcent  = Central Wavelength, defaulted to session keyword \\
                     WCENT.
\ap\pa
            fr_sp  = frame specifications, as npix,start,step 
\ap\pa
            line   = Name of line table, defaulted to keyword LINTAB
\ap\pa
            cat    = Name of line catalog, defaulted to keyword LINCAT
\ap\pa
            mode   = Method (LINEAR,1D,3D,NOLINEAR). Default: LINEAR
\ap\pa
            range  = Range of influence function. Default: 2.5
\ap\pa
            vflag  = Visualisation flag (Keep/NoKeep/Visualize) \\
                     Keep will store the HT on disk (in file middummh.bdf) \\
                     Visualize will display the HT.
\ap\no
Note:       
            For a description of the method see Ballester, 1994, 
            Astron. Astrophys., 286, pp. 1011-1018.
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Examples:
\ex
            DISPERSION/HOUGH  ? ? {IMSIZE(1)},1.,1.  
\xe \sxe