RBNRPSF (Feb95)              ftools.caltools             RBNRPSF (Feb95)



NAME
    rbnrpsf - rebins a radial PSF dataset
    
    
USAGE
    rbnrpsf infile outfile c_min
    
    
DESCRIPTION
    
      rbnrpsf reads an i/p  FITS  datafile  containing  a  radial  point
    spread  function  dataset  in  OGIP-standard  format, and rebins the
    dataset such that such that each new bin  contains  a  user-supplied
    minimum  number  of  counts.  The result is written in the form of a
    BINTABLE (with extname = OBS RPSF) in  the  output  file  (again  in
    OGIP  standard  format).  Details  of the o/p file formats supported
    can be found in the OGIP Calibration Memo  CAL/GEN/92-020  available
    via  the  OGIP  anonymous  ftp  account  on legacy.gsfc.nasa.gov (in
    Postscript) as caldb/docs/memos/cal_gen_92_020.ps.
    
      The number of ('source') counts in each radial bin  is  calculated
    after  the subtraction of an appropriate background. By default this
    background is obtained from the  BACKGRND  keyword  within  the  i/p
    file  (and  may  be zero).  However users may override this value by
    entering their own (see below).
    
    
    
WARNINGS ON USAGE
    
      You need to specify the extension number when specifying the  name
    of  the  input  FITS  file. If the input filename is infile.fits and
    the  extension  for  radial  profile  is  2,  then  it   should   be 
    infile.fits[2].
    
      If  a  radial  profile  has  been  background  subtracted, with an
    overestimate  for  the  background  rate,  negative  counts  can  be 
    present  in  the  input  datafile. It is important to note that when
    PCRPSF  performs  the   rebinning,   these   negative   values   are 
    (negatively)  included within the summation to determine whether the
    requested number of minimum counts are in the new bin.   This  often
    results in wide output bins.
    
      In  order  to  obtain a good resolution extract the radial profile
    with many steps, for example, if the extraction is performed from  0
    to 10 arcminutes, use at least 80 steps.
    
    
    
PARAMETERS
    
    infile [character string]
         The   input  filename  (produced  by  st2rpsf)  containing  the 
        1-dimensional radial profile of a source.
    
    outfile [character string]
         The name of the output file to be  created  (in  OGIP  standard
        format),  containing  an  extension  with  the  rebinned  radial 
        profile dataset.
    
    c_min [integer]
         Minimum number of counts per bin, for rebinning purposes.
    
    bkgd [character string (real value parsed)]
         Background count rate (in counts per  pixel)  should  the  user
        wish  to   override the value written in the BACKGRND keyword in
        the i/p file.   The special/default value ("%")  indicates  that
        the  value  from  the i/p  data file should be used. The special
        character  "CALC"  indicates  that   the  background  should  be 
        calculated.  NOTE:  If the background value  is changed then the
        sum of the source counts has to be  adjusted  (SUMRCTS   keyword
        in datafile).
    
    bkgd_rad [real]
         Only  prompted for if bkgd="CALC". This is the inner radius for
        background  calculation. NOTE: For Rosat PSPC  an  inner  radius
        less  than  2  arcmins   is  not  recommended  as the background
        estimate could be contaminated by  the PSF. For ROSAT  HRI  data
        an inner radius less than 1/2 arcmin is  not recommended.
    
    chatter [chattiness flag (hidden)]
         The  value  of  the  chatter  flag,  useful  for  reassurance &
        diagostics  purposes. The  default  value  is  chatter=10,  with
        chatter  <=  5  being very  quite and chatter >= 20 very verbose
        (silly).
    
    (clobber = false) [boolean]
         Flag specifying whether or not a  pre-existing  file  with  the
        same  name  as that  requested as the output file from this task
        will be overwritten.
    
    
    
BUGS
      You need to specify the extension number when specifying the  name
    of  the  input  FITS  file.  For  example,  if the input filename is
    infile.fits and the extension for  radial  profile  is  2,  then  it
    should be infile.fits[2].
    
    
SEE ALSO
     The ftools/caltools task st2rpsf
     The ftools/caltools task rpsfqdp
     The ftools/caltools task calcrpsf
     The ftools/rosat task pcrpsf
    
    
    
PRIMARY AUTHOR
    
    Rehana Yusaf
    HEASARC
    NASA/GSFC
    http://heasarc.gsfc.nasa.gov/cgi-bin/ftoolshelp