15.5.69 c2t00a

c2t00a(jdtt, jdut, xp, yp)

[SOFA] Returns the celestial-to-terrestrial matrix, given TT Julian Date jdtt, UT1 Julian Date jdut, and polar coordinates xp, yp, using the IAU 2000A nutation model.

jdtt and jdut should express the same instants of time: the first one in the TT timescale, and the second one in the UT1 timescale. xp, yp are the coordinates (in radians) of the Celestial Intermediate Pole with respect to the International Terrestrial Reference System measured along the meridians to 0 and 90 degrees west, respectively, for those same instants. All four arguments must have the same dimensions.

The result gets the same dimensions as all of the parameters, with two dimensions equal to 3 prefixed.

c2t00b yields slightly less accurate results, but faster.

See also: c2t00b, c2t06a, Astronomical Coordinate Calculations