Convert star RA,Dec from mean place to geocentric apparent palMap
Calls palMappa and palMapqk
The reference systems and timescales used are IAU 2006.
EQ is the Julian epoch specifying both the reference frame and the epoch of the position - usually 2000. For positions where the epoch and equinox are different, use the routine palPm to apply proper motion corrections before using this routine.
The distinction between the required TDB and TT is always negligible. Moreover, for all but the most critical applications UTC is adequate.
The proper motions in RA are dRA/dt rather than cos(Dec)dRA/dt.
This routine may be wasteful for some applications because it recomputes the Earth position/velocity and the precession- nutation matrix each time, and because it allows for parallax and proper motion. Where multiple transformations are to be carried out for one epoch, a faster method is to call the palMappa routine once and then either the palMapqk routine (which includes parallax and proper motion) or palMapqkz (which assumes zero parallax and proper motion).
The accuracy is sub-milliarcsecond, limited by the precession-nutation model (see palPrenut for details).
The accuracy is further limited by the routine palEvp, called by palMappa, which computes the Earth position and velocity. See eraEpv00 for details on that calculation.