palDs2tp palDs2tp - Spherical to tangent plane projection

Description:
Projection of spherical coordinates onto tangent plane: "gnomonic" projection - "standard coordinates"

Invocation:
palDs2tp( double ra, double dec, double raz, double decz, double $*$xi, double $*$eta, int $*$j );

Arguments:

ra = double (Given)
RA spherical coordinate of point to be projected (radians)
dec = double (Given)
Dec spherical coordinate of point to be projected (radians)
raz = double (Given)
RA spherical coordinate of tangent point (radians)
decz = double (Given)
Dec spherical coordinate of tangent point (radians)
xi = double $*$ (Returned)
First rectangular coordinate on tangent plane (radians)
eta = double $*$ (Returned)
Second rectangular coordinate on tangent plane (radians)
j = int $*$ (Returned)
status: 0 = OK, star on tangent plane 1 = error, star too far from axis 2 = error, antistar on tangent plane 3 = error, antistar too far from axis