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# lteceq

erfa.lteceq(epj, dl, db)

  Transformation from ecliptic coordinates (mean equinox and ecliptic of date) to ICRS RA,Dec, using a long-term precession model.

  Parameters
    epj double array
    dl double array
    db double array
  Returns
    dr double array
    dd double array

  Notes

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

      - - - - - - - - - -
       e r a L t e c e q
      - - - - - - - - - -

      Transformation from ecliptic coordinates (mean equinox and ecliptic
      of date) to ICRS RA,Dec, using a long-term precession model.

      Given:
         epj     double     Julian epoch (TT)
         dl,db   double     ecliptic longitude and latitude (radians)

      Returned:
         dr,dd   double     ICRS right ascension and declination (radians)

      1) No assumptions are made about whether the coordinates represent
         starlight and embody astrometric effects such as parallax or
         aberration.

      2) The transformation is approximately that from ecliptic longitude
         and latitude (mean equinox and ecliptic of date) to mean J2000.0
         right ascension and declination, with only frame bias (always
         less than 25 mas) to disturb this classical picture.

      3) The Vondrak et al. (2011, 2012) 400 millennia precession model
         agrees with the IAU 2006 precession at J2000.0 and stays within
         100 microarcseconds during the 20th and 21st centuries.  It is
         accurate to a few arcseconds throughout the historical period,
         worsening to a few tenths of a degree at the end of the
         +/- 200,000 year time span.

      Called:
         eraS2c       spherical coordinates to unit vector
         eraLtecm     J2000.0 to ecliptic rotation matrix, long term
         eraTrxp      product of transpose of r-matrix and p-vector
         eraC2s       unit vector to spherical coordinates
         eraAnp       normalize angle into range 0 to 2pi
         eraAnpm      normalize angle into range +/- pi

      References:

        Vondrak, J., Capitaine, N. and Wallace, P., 2011, New precession
        expressions, valid for long time intervals, Astron.Astrophys. 534,
        A22

        Vondrak, J., Capitaine, N. and Wallace, P., 2012, New precession
        expressions, valid for long time intervals (Corrigendum),
        Astron.Astrophys. 541, C1

      This revision:  2021 May 11

      Copyright (C) 2013-2021, NumFOCUS Foundation.
      Derived, with permission, from the SOFA library.  See notes at end of file.