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# ee00a

erfa.ee00a(date1, date2)

  Equation of the equinoxes, compatible with IAU 2000 resolutions.

  Parameters:
    date1 double array
    date2 double array
  Returns:
    c_retval double array

  Notes

  Wraps ERFA function `eraEe00a`. The ERFA documentation is:

      - - - - - - - - -
       e r a E e 0 0 a
      - - - - - - - - -

      Equation of the equinoxes, compatible with IAU 2000 resolutions.

      Given:
         date1,date2  double    TT as a 2-part Julian Date (Note 1)

      Returned (function value):
                      double    equation of the equinoxes (Note 2)

      Notes:

      1) The TT date date1+date2 is a Julian Date, apportioned in any
         convenient way between the two arguments.  For example,
         JD(TT)=2450123.7 could be expressed in any of these ways,
         among others:

                date1          date2

             2450123.7           0.0       (JD method)
             2451545.0       -1421.3       (J2000 method)
             2400000.5       50123.2       (MJD method)
             2450123.5           0.2       (date & time method)

         The JD method is the most natural and convenient to use in
         cases where the loss of several decimal digits of resolution
         is acceptable.  The J2000 method is best matched to the way
         the argument is handled internally and will deliver the
         optimum resolution.  The MJD method and the date & time methods
         are both good compromises between resolution and convenience.

      2) The result, which is in radians, operates in the following sense:

            Greenwich apparent ST = GMST + equation of the equinoxes

      3) The result is compatible with the IAU 2000 resolutions.  For
         further details, see IERS Conventions 2003 and Capitaine et al.
         (2002).

      Called:
         eraPr00      IAU 2000 precession adjustments
         eraObl80     mean obliquity, IAU 1980
         eraNut00a    nutation, IAU 2000A
         eraEe00      equation of the equinoxes, IAU 2000

      References:

         Capitaine, N., Wallace, P.T. and McCarthy, D.D., "Expressions to
         implement the IAU 2000 definition of UT1", Astronomy &
         Astrophysics, 406, 1135-1149 (2003).

         McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
         IERS Technical Note No. 32, BKG (2004).

      This revision:  2021 May 11

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