**ACTION:**- Form the matrix of nutation (IAU 1980 theory) for a given date.
**CALL:**`CALL sla_NUT (DATE, RMATN)`

**GIVEN:**-

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

**RETURNED:**-

*RMATN***D(3,3)**nutation matrix

**NOTE:**- The matrix is in the sense:

where**v**_{true}=**M****v**_{mean}**v**_{true}is the star vector relative to the true equator and equinox of date,**M**is the 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.

Starlink User Note 67

P. T. Wallace

12 October 1999

E-mail:ptw@star.rl.ac.uk