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)

GIVEN:

EP0 beginning epoch

EP1 D ending epoch

RETURNED:

RMATP precession matrix

NOTES:

1.

The epochs are TDB Julian epochs.

2.

The matrix is in the sense:

v₁ = M$\cdot$v₀

where v₁ is the star vector relative to the mean equator and equinox of epoch EP1, M is the $3\times3$ matrix RMATP and v₀ 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 $0\hspace{-0.05em}^{'\hspace{-0.1em}'}\hspace{-0.4em}.3$ per 1000 years. The remainder of the formulation provides a precision of 1 milliarcsecond over the interval from 1000AD to 3000AD, $0\hspace{-0.05em}^{'\hspace{-0.1em}'}\hspace{-0.4em}.1$ from 1000BC to 5000AD and $1\hspace{-0.05em}^{'\hspace{-0.1em}'}$ from 4000BC to 8000AD.

REFERENCE:

Simon, J.L. et al., 1994. Astr.Astrophys. 282, 663.