function Querygsc, target, dis,magrange = magrange, HOURS = hours, $
   VERBOSE=verbose, BOX = box
;+
; NAME: 
;   QUERYGSC
;
; PURPOSE: 
;   Query the Guide Star Catalog (GSC V2.3.2) at STScI by position
; 
; EXPLANATION:
;   Uses the IDL SOCKET command to query the GSC 2.3.2 database over the Web.
;   The number and names of the structure tags was changed in September 2015
;
;   Alternatively, (and more reliably) one can query the GSC 2.3.2 catalog using
;   queryvizier.pro and the VIZIER database, e.g.  
;     IDL> st = queryvizier('GSC2.3',[23,35],10,/all)
; 
;   GSC2.3 is an all-sky export of calibrated photographic survey plate 
;   source parameters from the COMPASS database.  The number of unique
;   objects is approximately 945,592,683.   All sources are 
;   from the second-generation plate-processing pipeline with the exception
;   of Tycho-2 and Skymap sources in the case of very bright objects. The 
;   Skymap sources are exported when there is no matching GSC or Tycho 
;   sources.  Each GSC 2.3 entry contains only one position and one 
;   magnitude per bandpass for each unique sky object
;
; CALLING SEQUENCE: 
;     info = QueryGSC(targetname_or_coords, [ dis, /HOURS] )
;
; INPUTS: 
;      TARGETNAME_OR_COORDS - Either a scalar string giving a target name, 
;          (with J2000 coordinates determined by SIMBAD), or a 2-element
;          numeric vector giving the J2000 right ascension in *degrees* (or 
;          hours if /HOURS is set) and the target declination in degrees.
;
; OPTIONAL INPUT:
;    dis - Numeric scalar giving search radius in arcminutes to search around 
;          specified target    Default is 5 arcminutes
;
; OPTIONAL INPUT KEYWORDS:
;
;    /BOX - if set, then radius gives  a box width in arcminutes
;    /HOURS - If set, then the right ascension is both input and output (in
;             the info .ra tag) in hours instead of degrees
;    /VERBOSE - If set, then the CGI command to the Webserver will be displayed
;;
; OUTPUTS: 
;   info - IDL structure containing information on the GSC stars within the 
;          specified distance of the specified center.   There are (currently)
;          48 tags in this structure  -- for further information see
;          http://gsss.stsci.edu/Catalogs/GSC/GSC2/gsc23/gsc23_release_notes.htm
;

;          .GSC2ID - GSC2 name
;          .GSC1ID - GSC1 name
;          .HSTID - GSC 2.3 name for HST operations
;          .RA,.DEC - Position in degrees (double precision).   RA is given in
;                   hours if the /HOURS keyword is set.
;          .EPOCH - mean epoch of the observation
;          .RAEPSILON, .DECEPSION - uncertainty (in arcseconds) in the RA and 
;                   Dec
;          .FPGMAG, .FPGERR, .FPGMAGCODE - mag, error, code in photographic F
;          .JPGMAG, .JPGERR, .JPGMAGCODE - mag, error code, photographic J
;          .VPGMAG, .VPGERR, .VPGMAGCODE - V mag, error, code
;          .NPGMAG, .NPGERR, .NPGMAGCODE - mag, error, code
;          .UMAG, .UERR, .UMAGCODE - magnitude, error, code
;          .BMAG, .BERR, .BMAGCODE - magnitude, error, code
;          .VMAG, .VERR, .VMAGCODE - magnitude, error, code
;          .RMAG, .RERR, .RMAGCODE - magnitude, error, code
;          .IMAG, .IERR, .IMAGCODE - magnitude, error, code
;          .JMAG, .JERR, .JMAGCODE - magnitude, error, code
;          .HMAG, .HERR, .HMAGCODE - magnitude, error, code
;          .KMAG, .KERR, .KMAGCODE - magnitude, error, code
;          .CLASS - classification (0-5): 0-star, 1-galaxy, 2-blend, 
;          .SEMIMAJORAXIS - semi-major axis in pixels
;          .POSITIONANGLE - Position angle of extended objects in degrees
;                         3-nonstar, 4-unclassified, 5-defect
;          .SOURCESTATUS -10 digit field  used to encode more detailed information 
;              about the properties of the catalog object.   For more info, see
;http://www-gsss.stsci.edu/Catalogs/GSC/GSC2/gsc23/gsc23_release_notes.htm#ClassificationCodes
;           .VARIABLEFLAG, MULTIPLEFLAG - Variability andd multiplicity flags
;            COMPASSGSC2ID - Unique ID in the Compass database 
;            http://gsss.stsci.edu/zzzOldWebSite/compass/CompassHome.htm
; EXAMPLE: 
;          Plot a histogram of the photographic J magnitudes of all GSC 2.3.2 
;          stars within 10 arcminutes of the center of the globular cluster M13 
;
;          IDL> info = querygsc('M13',10)
;          IDL> plothist,info.jpgmag,xran=[10,20]
;
; PROCEDURES USED:
;          QUERYSIMBAD, RADEC, WEBGET()
;
; MODIFICATION HISTORY: 
;         Written by W. Landsman  SSAI  August 2002
;         Fixed parsing of RA and Dec  W. Landsman September 2002
;         Major rewrite to use new STScI Web server, remove magrange
;           keyword   W. Landsman Dec 2007
;         Update server name, added /BOX,/ VERBOSE keywords W.L 19 Dec 2007
;         Web server now also returns infrared data  W.L. Feb 2010
;         Fixed case where dec neg. and deg or min 0 Pat Fry Jul 2010
;         Updated for new server format W. Landsman  April 2014
;         Updated for new server format W. Landsman  September 2015
;
;-
  compile_opt idl2
  if N_params() LT 2 then begin
       print,'Syntax - info = QueryGSC(targetname_or_coord, dis,'
       print,'                        [/Hours, /Box, /VERBOSE} )'
       print,'   RA (degrees), Dec (degrees) -- search coordinates of center)'
       print,'  dis -- search radius in arcminutes'
       if N_elements(info) GT 0 then return,info else return, -1
  endif
  if N_elements(dis) EQ 0 then dis = 5
    if N_elements(target) EQ 2 then begin
      ra = float(target[0])
      dec = float(target[1])
  endif else begin
       QuerySimbad, target, ra,dec, Found = Found
       if found EQ 0 then message,'Target name ' + target + $
                 ' could not be translated by SIMBAD'
  endelse  
  radius = keyword_set(box)? 'Box' : 'Radius'
  
   radec,ra,dec,hr,mn,sc,deg,dmn,dsc,hours=keyword_set(hours)
   deg = string(deg,'(i3.2)')
   dsn = strmid(deg,0,1)
   deg = strmid(deg,1,2)
   if (dmn lt 0 || dsc lt 0) then begin
       dmn = abs(dmn)
       dsc = abs(dsc)
       dsn = '-'
   endif
   sc = round(sc)
   dsc = round(dsc)
   if dsn EQ ' ' then dsn = '%2B'
  ;;
  QueryURL = "http://gsss.stsci.edu/webservices/vo/CatalogSearch.aspx?" + $
   'RA=' + strtrim(ra,2)  + '&Dec=' + strtrim(dec,2) + $
    '&SR=' + strtrim(dis/60.,2) + $
    '&FORMAT=CSV&CAT=GSC23'

    
  if keyword_set(verbose) then print,queryurl
  ;;  
  Result = webget(QueryURL)
 ;
  t = result.text

  nstar = N_elements(t) -2
  if strmid(t[0],0,5) NE 'Usage' and nstar GT 0 THEN BEGIN
  headers = strsplit(t[1],',',/extract)
  
  info = create_struct(Name='gsc',headers, 0LL,'','','', $
   0.0d,0.0d, 0.0,0.0,0.0, $
     0.0, 0.0, 0, $   ;Fpgmag,Err,code
   0.0, 0.0, 0, $   ;Jpgmag,Err,code
    0.0, 0.0, 0, $   ;Vmag,Err,code
       0.0, 0.0, 0, $   ;Nmag,Err,code 
  0.0, 0.0, 0, $   ;Umag,Err,code
    0.0, 0.0, 0, $   ;Bmag,Err,code
  0.0, 0.0, 0, $   ;Rmag,Err,code
    0.0, 0.0, 0, $   ;Imag,Err,code
  0.0, 0.0, 0, $   ;Jmag,Err,code
   0.0, 0.0, 0, $   ;Hmag,Err,code
   0.0, 0.0, 0, $   ;Kmag,Err,code
   0,  $   ;Classification 
   0.,  $   ;Size
   0., 0., 0LL, $   eccentricity, positionangle, objectflags
   0, 0 , $ ;variable, Multiple flag
   0LL, '' )
 


  info = replicate(info,nstar)

  for i=0,nstar-1 do begin
      temp = strtrim(strsplit(t[i+2],',',/extract),2)
       for j=0,N_elements(temp)-1 do begin 
       info[i].(j) = temp[j]      
       endfor
  endfor
   ENDIF ELSE BEGIN 
      message, 'No objects returned by server. The server answered:', /info
      print, Result.Text
      if N_elements(info) GT 0 then return, info else return, -1
  ENDELSE 
  if keyword_set(hours) then info.ra = info.ra/15.0d 
 return,info
END