What precession routine has NED adopted?
A.: NED adopted the FK5 system in 1992 with J2000.0 as the default equinox. The precession routine is essentially that described in the introduction to FK5, with minor changes to support the work then being done at IPAC. J. Bennett, the author of the routine, has provided an extensive description of NED’s precession calculations. Though NED does not yet explicitly support the International Celestial Reference Frame (ICRF), the FK5 optical system is consistent with ICRF to within the known errors of the FK5 system (see e.g. Ma et al. AJ 116, 516, 1998). • Q.: Is there an easy way to change coordinate systems? A.: NED’s coordinate calculator (see the previous question) will handle transformation from one coordinate system to another. It currently handles transformations among the ecliptic, equatorial, Galactic, and supergalactic coordinate systems. • Q.: What kind of magnitude is listed in the Basic Data? A.: These are usually optical magnitudes taken from the astronomical literature, an
