Once you have set up a Plot to draw a coordinate grid
(), it is a simple matter to change things so
that the grid represents a different celestial coordinate system. For
example, after creating the Plot with astPlot, you could use:
or:astSet( plot, "System=Galactic" );
astSet( plot, "System=FK5, Equinox=J2010" );
and any axes and/or grid drawn subsequently would represent the new
celestial coordinate system you specified. Note, however, that this
will only work if the original grid represented celestial coordinates
of some kind (see for how to
determine if this is the case
). If it did not,
you will get an error message.
For more information about the celestial coordinate systems available,
see the descriptions of the System, Equinox and Epoch attributes in
.
AST A Library for Handling World Coordinate Systems in Astronomy