numat¶
- erfa.numat(epsa, dpsi, deps)[source]¶
Form the matrix of nutation.
- Parameters:
- epsadouble array
- dpsidouble array
- depsdouble array
- Returns:
- rmatndouble array
Notes
Wraps ERFA function
eraNumat
. The ERFA documentation is:- - - - - - - - - e r a N u m a t - - - - - - - - - Form the matrix of nutation. Given: epsa double mean obliquity of date (Note 1) dpsi,deps double nutation (Note 2) Returned: rmatn double[3][3] nutation matrix (Note 3) Notes: 1) The supplied mean obliquity epsa, must be consistent with the precession-nutation models from which dpsi and deps were obtained. 2) The caller is responsible for providing the nutation components; they are in longitude and obliquity, in radians and are with respect to the equinox and ecliptic of date. 3) The matrix operates in the sense V(true) = rmatn * V(mean), where the p-vector V(true) is with respect to the true equatorial triad of date and the p-vector V(mean) is with respect to the mean equatorial triad of date. Called: eraIr initialize r-matrix to identity eraRx rotate around X-axis eraRz rotate around Z-axis Reference: Explanatory Supplement to the Astronomical Almanac, P. Kenneth Seidelmann (ed), University Science Books (1992), Section 3.222-3 (p114). This revision: 2021 May 11 Copyright (C) 2013-2023, NumFOCUS Foundation. Derived, with permission, from the SOFA library. See notes at end of file.