SLA_NUT - Nutation Matrix   

ACTION:

Form the matrix of nutation (IAU 1980 theory) for a given date.

CALL:

CALL sla_NUT (DATE, RMATN)

GIVEN:

DATE TDB (formerly ET) as Modified Julian Date (JD-2400000.5)

RETURNED:

RMATN nutation matrix

NOTE:

The matrix is in the sense:

v_true = M$\cdot$v_mean

where v_true is the star vector relative to the true equator and equinox of date, M is the $3\times3$ matrix RMATN and v_mean is the star vector relative to the mean equator and equinox of date.

REFERENCES:

1.

Final report of the IAU Working Group on Nutation, chairman P.K.Seidelmann, 1980.

2.

Kaplan, G.H., 1981. USNO circular No. 163, pA3-6.