erfa.pr00(date1, date2)[source]

Precession-rate part of the IAU 2000 precession-nutation models (part of MHB2000).

date1double array
date2double array
dpsiprdouble array
depsprdouble array


Wraps ERFA function eraPr00. The ERFA documentation is:

- - - - - - - -
 e r a P r 0 0
- - - - - - - -

Precession-rate part of the IAU 2000 precession-nutation models
(part of MHB2000).

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

   dpsipr,depspr  double  precession corrections (Notes 2,3)


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 precession adjustments are expressed as "nutation
   components", corrections in longitude and obliquity with respect
   to the J2000.0 equinox and ecliptic.

3) Although the precession adjustments are stated to be with respect
   to Lieske et al. (1977), the MHB2000 model does not specify which
   set of Euler angles are to be used and how the adjustments are to
   be applied.  The most literal and straightforward procedure is to
   adopt the 4-rotation epsilon_0, psi_A, omega_A, xi_A option, and
   to add dpsipr to psi_A and depspr to both omega_A and eps_A.

4) This is an implementation of one aspect of the IAU 2000A nutation
   model, formally adopted by the IAU General Assembly in 2000,
   namely MHB2000 (Mathews et al. 2002).


   Lieske, J.H., Lederle, T., Fricke, W. & Morando, B., "Expressions
   for the precession quantities based upon the IAU (1976) System of
   Astronomical Constants", Astron.Astrophys., 58, 1-16 (1977)

   Mathews, P.M., Herring, T.A., Buffet, B.A., "Modeling of nutation
   and precession   New nutation series for nonrigid Earth and
   insights into the Earth's interior", J.Geophys.Res., 107, B4,
   2002.  The MHB2000 code itself was obtained on 9th September 2002

   Wallace, P.T., "Software for Implementing the IAU 2000
   Resolutions", in IERS Workshop 5.1 (2002).

This revision:  2021 May 11

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