gcirc¶
-
pydl.goddard.astro.
gcirc
(ra1, dec1, ra2, dec2, units=2)[source]¶ Computes rigorous great circle arc distances.
Parameters: - ra1, dec1, ra2, dec2 :
float
or array-like RA and Dec of two points.
- units : { 0, 1, 2 }, optional
- units = 0: everything is already in radians
- units = 1: RA in hours, dec in degrees, distance in arcsec.
- units = 2: RA, dec in degrees, distance in arcsec (default)
Returns: - :class:`float` or array-like
The angular distance. Units of the value returned depend on the input value of
units
.
Notes
The formula below is the one best suited to handling small angular separations. See: http://en.wikipedia.org/wiki/Great-circle_distance
- ra1, dec1, ra2, dec2 :