SLA_PRECL

Precession Matrix (latest)

ACTION:: Form the matrix of precession between two epochs, using the model of Simon et al. (1994), which is suitable for long periods of time.
CALL:: CALL sla_PRECL (EP0, EP1, RMATP)

RMATP	D(3,3)	precession matrix

NOTES:

(1): The epochs are TDB Julian epochs.
(2): The matrix is in the sense:

v $_{1}$ = M $\cdot$ v $_{0}$
where v $_{1}$ is the star vector relative to the mean equator and equinox of epoch EP1, M is the $3 \times 3$ matrix RMATP and v $_{0}$ is the star vector relative to the mean equator and equinox of epoch EP0.
(3): The absolute accuracy of the model is limited by the uncertainty in the general precession, about ′′03 per 1000 years. The remainder of the formulation provides a precision of 1 milliarcsecond over the interval from 1000 AD to 3000 AD, ′′01 from 1000 BC to 5000 AD and $1$ $^{'}^{'}$ from 4000 BC to 8000 AD.