SAOimage display of M-51

World Coordinate Systems in SAOimage

SAO/TDC Home Page

Five WCS modes

  • 27 proposed FITS standard WCS types
  • Digital Sky Survey plate solutions
  • approximate plate-tangent WCS given a plate center and scale
  • IRAF TNX polynomial projection.
  • SAO polynomial projection.

    Keyboard and Cursor Commands

    Command Line Options

    Multiple WCS Support


    Example 1. Append the WCS position for the current cursor location to a file
    Example 2. Use sgsc to identify the closest HST Guide Star
    Example 3. Find an image star in various catalogs.
    Example 4. Use imcat to display catalog stars on an image with a WCS.

    Setting an Image WCS

    imwcs has been developed to set the WCS of an image by matching stars images to a catalog, such as the HST Guide Star Catalog or the USNO A 1.0 Catalog, with no user interaction.


    The subroutine library, libwcs, used by SAOimage is available for inclusion in other programs.