tttdb¶
-
erfa.
tttdb
(tt1, tt2, dtr)[source]¶ Wrapper for ERFA function
eraTttdb
.- Parameters
tt1 : double array
tt2 : double array
dtr : double array
- Returns
tdb1 : double array
tdb2 : double array
Notes
The ERFA documentation is below.
- - - - - - - - - e r a T t t d b - - - - - - - - - Time scale transformation: Terrestrial Time, TT, to Barycentric Dynamical Time, TDB. Given: tt1,tt2 double TT as a 2-part Julian Date dtr double TDB-TT in seconds Returned: tdb1,tdb2 double TDB as a 2-part Julian Date Returned (function value): int status: 0 = OK Notes: 1) tt1+tt2 is Julian Date, apportioned in any convenient way between the two arguments, for example where tt1 is the Julian Day Number and tt2 is the fraction of a day. The returned tdb1,tdb2 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 Copyright (C) 2013-2019, NumFOCUS Foundation. Derived, with permission, from the SOFA library. See notes at end of file.