eors¶

erfa.eors(rnpb, s)[source]¶

Equation of the origins, given the classical NPB matrix and the quantity s.

Parameters:

rnpbdouble array
sdouble array

Returns:

c_retvaldouble array

Notes

Wraps ERFA function eraEors. The ERFA documentation is:

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  e r a E o r s
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 Equation of the origins, given the classical NPB matrix and the
 quantity s.

 Given:
    rnpb  double[3][3]  classical nutation x precession x bias matrix
    s     double        the quantity s (the CIO locator) in radians

 Returned (function value):
          double        the equation of the origins in radians

 Notes:

 1)  The equation of the origins is the distance between the true
     equinox and the celestial intermediate origin and, equivalently,
     the difference between Earth rotation angle and Greenwich
     apparent sidereal time (ERA-GST).  It comprises the precession
     (since J2000.0) in right ascension plus the equation of the
     equinoxes (including the small correction terms).

 2)  The algorithm is from Wallace & Capitaine (2006).

References:

    Capitaine, N. & Wallace, P.T., 2006, Astron.Astrophys. 450, 855

    Wallace, P. & Capitaine, N., 2006, Astron.Astrophys. 459, 981

 This revision:  2023 May 6

 Copyright (C) 2013-2023, NumFOCUS Foundation.
 Derived, with permission, from the SOFA library.  See notes at end of file.

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eors¶