15.5.470 pvstar

pvstar, pv, ra, dec, pmr, pmd, px, rv

[SOFA] Converts position-velocity matrix pv (AU, AU/d) to catalog coordinates right ascension ra (rad), declination dec (rad), right ascension proper motion pmr (rad/Ja), declination proper motion pmd (rad/Ja), parallax px (arcsec), and radial velocity rv (km/s receding). pv must have 2 elements in its first dimension and 3 in its second dimension. The output parameters get the same dimensions as pv except that the first two dimensions (equal to 2 and 3) are omitted.

The returned star data are observables for an imaginary observer at the solar-system barycenter. Proper motion and radial velocity are in terms of barycentric coordinate time (tcb). For most practical applications, the distinction between tcb and Terrestrial Time (TT/TAI) may be neglected. Usually the result is limited by the intrinsic accuracy of the proper-motion and radial-velocity data.

In accordance with normal star-catalog conventions, the object’s right ascension and declination are freed from the effects of secular aberration. The frame is aligned to the catalog equator and equinox, is Lorentzian and centered on the ssb.

The proper motions are measured in radians per Julian year.

See also: Astronomical Coordinate Calculations