GONGPREP(1)

NAME

     gongprep - process raw GONG data images

SYNOPSIS

     gongprep [-cqv] [argument= value ...]

DESCRIPTION

     gongprep provides the necessary preprocessing of a series of
     raw  GONG Dopplergrams for mapping into heliographic coordi-
     nates.  The sky position angle and physical ephemerides  are
     calculated  from  the  time, and the center and radii of the
     best fit ellipse to the limb are determined for each  image.
     Mainly it just sets a bunch of attributes in the dataset.

     The -c option applies a constant calibration factor  to  the
     input values.

     The -q option prints out the list of required arguments  and
     their  default  or environmental values, then quits.  The -v
     option sets verbose mode, redirecting history from stdout to
     stderr.

OPTIONS

     in=Dataset_Name     input dataset (default: gong.fits)

     out=Dataset_Name    output         dataset         (default:
                         gong.prepped.fits)

     calib=Real          calibration factor (default: -1.0)

     rc=Real             semi-major  axis  of  ellipse  on  image
                         beyond which values are ignored for pur-
                         poses  of   determining   the   gradient
                         (default: 0.5)

     start_t=String      starting time of the  dataset  (default:
                         1991:06:30_15h:14m)

     ref_t=String        time at which the sky position angle  is
                         0 (default: 1991:06:30_07h:39m)

     delta_t=String      temporal cadence of  succesive  sequence
                         numbers in the dataset (default: 60s)

EXAMPLES

FILES

SEE ALSO

     sds_gongprep(3), solephem(3)

DIAGNOSTICS

BUGS

     The module is probably obsolescent.  It would be  better  to
     do  something  than  to  just  rewrite  the dataset with new
     headers.

     The fitting of the  velocity  gradient  to  verify  position
     angle  is  not  actually used.  The limb fit must already be
     supplied in the input data.  Several of the output attribute
     have a mismatch between declared type and attribute type.

AUTHOR

     Kay Leibrand

HISTORY

     1994-02-14     SOI Version 0.8