utctai¶
- erfa.utctai(utc1, utc2)[source]¶
Time scale transformation: Coordinated Universal Time, UTC, to International Atomic Time, TAI.
- Parameters:
- utc1double array
- utc2double array
- Returns:
- tai1double array
- tai2double array
Notes
Wraps ERFA function
eraUtctai
. The ERFA documentation is:- - - - - - - - - - e r a U t c t a i - - - - - - - - - - Time scale transformation: Coordinated Universal Time, UTC, to International Atomic Time, TAI. Given: utc1,utc2 double UTC as a 2-part quasi Julian Date (Notes 1-4) Returned: tai1,tai2 double TAI as a 2-part Julian Date (Note 5) Returned (function value): int status: +1 = dubious year (Note 3) 0 = OK -1 = unacceptable date Notes: 1) utc1+utc2 is quasi Julian Date (see Note 2), apportioned in any convenient way between the two arguments, for example where utc1 is the Julian Day Number and utc2 is the fraction of a day. 2) JD cannot unambiguously represent UTC during a leap second unless special measures are taken. The convention in the present function is that the JD day represents UTC days whether the length is 86399, 86400 or 86401 SI seconds. In the 1960-1972 era there were smaller jumps (in either direction) each time the linear UTC(TAI) expression was changed, and these "mini-leaps" are also included in the ERFA convention. 3) The warning status "dubious year" flags UTCs that predate the introduction of the time scale or that are too far in the future to be trusted. See eraDat for further details. 4) The function eraDtf2d converts from calendar date and time of day into 2-part Julian Date, and in the case of UTC implements the leap-second-ambiguity convention described above. 5) The returned TAI1,TAI2 are such that their sum is the TAI Julian Date. Called: eraJd2cal JD to Gregorian calendar eraDat delta(AT) = TAI-UTC eraCal2jd Gregorian calendar to JD References: McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003), IERS Technical Note No. 32, BKG (2004) Explanatory Supplement to the Astronomical Almanac, P. Kenneth Seidelmann (ed), University Science Books (1992) This revision: 2021 May 11 Copyright (C) 2013-2023, NumFOCUS Foundation. Derived, with permission, from the SOFA library. See notes at end of file.