ASTRD2SN

Name

astrd2sn

Purpose

Astrometry conversion from ($\alpha$,$\delta$) to ($\xi$,$\eta$)

Description

Standard coordinate conversion (see Smart, p283)

Calling Sequence

astrd2sn,ra,dec,racen,deccen,xi,eta

Inputs

ra - Right ascension (radians)
dec - Declination (radians)
racen - Right ascension of tangent point between plane and celestial sphere.
deccen - Declination of tangent point between plane and celestial sphere.

Optional Input Parameters

Keyword Input Parameters

ARCSEC - Flag, if set indicates that the output xi,eta values are in
arcseconds. Otherwise they are returned in radians.

Outputs

xi - Coordinate in tangent plane.
eta - Coordinate in tangent plane.

Keyword Output Parameters

Common Blocks

Side Effects

Restrictions

Procedure

Modification History

97/04/05 - Written by Marc W. Buie, Lowell Observatory
2009/12/08, MWB, added ARCSEC keyword