ee06a¶
- erfa.ee06a(date1, date2)[source]¶
Equation of the equinoxes, compatible with IAU 2000 resolutions and IAU 2006/2000A precession-nutation.
- Parameters:
- date1double array
- date2double array
- Returns:
- c_retvaldouble array
Notes
Wraps ERFA function
eraEe06a
. The ERFA documentation is:- - - - - - - - - e r a E e 0 6 a - - - - - - - - - Equation of the equinoxes, compatible with IAU 2000 resolutions and IAU 2006/2000A precession-nutation. 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 Called: eraAnpm normalize angle into range +/- pi eraGst06a Greenwich apparent sidereal time, IAU 2006/2000A eraGmst06 Greenwich mean sidereal time, IAU 2006 Reference: McCarthy, D. D., Petit, G. (eds.), 2004, IERS Conventions (2003), IERS Technical Note No. 32, BKG This revision: 2021 May 11 Copyright (C) 2013-2023, NumFOCUS Foundation. Derived, with permission, from the SOFA library. See notes at end of file.