Coordinate Systems for Solar Image Data

[William Thompson]

I would like to open up the following (PostScript) document for discussion
within the solar physics and FITS community:

	http://orpheus.nascom.nasa.gov/~thompson/papers/coordinates.ps

Here are the title and abstract:

		    COORDINATE SYSTEMS FOR SOLAR IMAGE DATA

			      William T. Thompson

    A set of formal systems for describing the coordinates of solar image
    data is proposed.  These systems build on current practice in applying
    coordinates to solar image data.  Both heliographic and heliocentric
    coordinates are discussed.  A distinction is also drawn between
    heliocentric and helioprojective coordinates, where the latter takes
    the observer's exact geometry into account.  The extension of these
    coordinate systems to observations made from non-terrestial viewpoints
    is discussed.  A formal system for incorporation of these coordinates
    into FITS files, based on the FITS World Coordinate System, is
    described, together with examples.

Thank you,

William Thompson