equinox, /julian, /besselian] [,
/fromequatorial, /fromecliptical, /fromgalactic] [, /toequatorial,
Transforms between the main astronomical coordinate systems (with all
coordinates measured in degrees).
longitudes or right ascensions.
latitudes or declinations. Where relevant, the coordinates are
assumed to be or are returned relative to the indicated
equinox, which is a Julian Date (if neither
/besselian is specified), or a Julian year
(e.g., 2000.0 = J2000.0) if
/julian is specified, or a
Besselian year (e.g., 1875.0 = B1875.0) if
specified. Besselian years are taken to be 365.2421988 days long, and
B1950.0 corresponds to JDE 2433282.4235. If
not specified, then J2000.0 is assumed. The result has the same
coords. By default,
/toecliptical is assumed.
See also: astron, precess