tdbtt¶

erfa.tdbtt(tdb1, tdb2, dtr)[source]¶

Time scale transformation: Barycentric Dynamical Time, TDB, to Terrestrial Time, TT.

Parameters:

tdb1double array
tdb2double array
dtrdouble array

Returns:

tt1double array
tt2double array

Notes

Wraps ERFA function eraTdbtt. The ERFA documentation is:

- - - - - - - - -
 e r a T d b t t
- - - - - - - - -

Time scale transformation:  Barycentric Dynamical Time, TDB, to
Terrestrial Time, TT.

Given:
   tdb1,tdb2  double    TDB as a 2-part Julian Date
   dtr        double    TDB-TT in seconds

Returned:
   tt1,tt2    double    TT as a 2-part Julian Date

Returned (function value):
              int       status:  0 = OK

Notes:

1) tdb1+tdb2 is Julian Date, apportioned in any convenient way
   between the two arguments, for example where tdb1 is the Julian
   Day Number and tdb2 is the fraction of a day.  The returned
   tt1,tt2 follow suit.

2) The argument dtr represents the quasi-periodic component of the
   GR transformation between TT and TCB.  It is dependent upon the
   adopted solar-system ephemeris, and can be obtained by numerical
   integration, by interrogating a precomputed time ephemeris or by
   evaluating a model such as that implemented in the ERFA function
   eraDtdb.   The quantity is dominated by an annual term of 1.7 ms
   amplitude.

3) TDB is essentially the same as Teph, the time argument for the
   JPL solar system ephemerides.

References:

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

   IAU 2006 Resolution 3

This revision:  2021 May 11

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

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tdbtt¶