idlastro / Astronomical Utilities: EQPOLE

[Source code]

NAME
EQPOLE
PURPOSE
Convert RA and Dec to X,Y using an equal-area polar projection.
EXPLANATION
The output X and Y coordinates are scaled to be between
-90 and +90 to go from equator to pole to equator. Output map points 
can be centered on the north pole or south pole.
CALLING SEQUENCE
EQPOLE, L, B, X, Y, [ /SOUTHPOLE ]
INPUTS
L - longitude - scalar or vector, in degrees
B - latitude - same number of elements as RA, in degrees
OUTPUTS
X - X coordinate, same number of elements as RA.   X is normalized to
        be between -90 and 90.
Y - Y coordinate, same number of elements as DEC.  Y is normalized to
        be between -90 and 90.
KEYWORDS
/SOUTHPOLE      - Keyword to indicate that the plot is to be centered 
        on the south pole instead of the north pole.
REVISION HISTORY
J. Bloch        LANL, SST-9     1.1     5/16/91
Converted to IDL V5.0   W. Landsman   September 1997