Name

       xy2sky - Compute RA Dec from X Y using WCS in FITS and IRAF image files

Synopsis

       xy2sky [-vbjg] [-n ndec] file.fts x1 y1 ... xn yn
       or
       xy2sky [-bdjgv] [-n ndec] file.fts @listfile

Description

       xy2sky  (pronounced X-Y-to-sky) is a utility for getting the world coordinates of a set of
       image coordinates in a FITS or IRAF image. World coordinate system  (WCS)  information  in
       the  image  header  describes, in a standard way, the relationship between sky coordinates
       and image pixels. This information is used by the program to  transform  image  coordinate
       (X,Y)  pairs  to right ascension and declination sky coordinate pairs. The current version
       of the program prints the coordinates at the same equinox as is given in the image header,
       but  future  versions  will  allow  transformations  to  B1950/FK4, J2000/FK5, or galactic
       coordinates. Input and output files in the Starbase format will eventually be allowed.

Options

       -a     Append input line after output position

       -b     B1950 (FK4) output

       -d     RA and Dec output in degrees

       -e     Output in ecliptic longitude and latitude in degrees.

       -f <number>
              Set third dimension for 3-D projections such as CSC

       -g     Galactic longitude and latitude output

       -i     First column is star id; 2nd, 3rd are x,y position

       -j     J2000 (FK5) output

       -m <number>
              Set mode for output of LINEAR WCS coordinates:  0: x y linear 1: x units y units 2:
              x y linear units units

       -n <number>
              Number of decimal places in output RA seconds

       -q <year>
              Output equinox if not 2000 (-j) or 1950 (-b)

       -t     Output as tab-separated table

       -v     More descriptive output -z Use AIPS classic projections instead of WCSLIB

See Also

       sky2xy(1)

Author

       Doug Mink, SAO (dmink@cfa.harvard.edu)