utcut1¶
- erfa.utcut1(utc1, utc2, dut1)[source]¶
Time scale transformation: Coordinated Universal Time, UTC, to Universal Time, UT1.
- Parameters:
- utc1double array
- utc2double array
- dut1double array
- Returns:
- ut11double array
- ut12double array
Notes
Wraps ERFA function
eraUtcut1
. The ERFA documentation is:- - - - - - - - - - e r a U t c u t 1 - - - - - - - - - - Time scale transformation: Coordinated Universal Time, UTC, to Universal Time, UT1. Given: utc1,utc2 double UTC as a 2-part quasi Julian Date (Notes 1-4) dut1 double Delta UT1 = UT1-UTC in seconds (Note 5) Returned: ut11,ut12 double UT1 as a 2-part Julian Date (Note 6) 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. 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) Delta UT1 can be obtained from tabulations provided by the International Earth Rotation and Reference Systems Service. It is the caller's responsibility to supply a dut1 argument containing the UT1-UTC value that matches the given UTC. 6) The returned ut11,ut12 are such that their sum is the UT1 Julian Date. 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) Called: eraJd2cal JD to Gregorian calendar eraDat delta(AT) = TAI-UTC eraUtctai UTC to TAI eraTaiut1 TAI to UT1 This revision: 2021 May 11 Copyright (C) 2013-2023, NumFOCUS Foundation. Derived, with permission, from the SOFA library. See notes at end of file.