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.