jd2cal¶
- erfa.jd2cal(dj1, dj2)[source]¶
Julian Date to Gregorian year, month, day, and fraction of a day.
- Parameters:
- dj1double array
- dj2double array
- Returns:
- iyint array
- imint array
- idint array
- fddouble array
Notes
Wraps ERFA function
eraJd2cal
. The ERFA documentation is:- - - - - - - - - - e r a J d 2 c a l - - - - - - - - - - Julian Date to Gregorian year, month, day, and fraction of a day. Given: dj1,dj2 double Julian Date (Notes 1, 2) Returned (arguments): iy int year im int month id int day fd double fraction of day Returned (function value): int status: 0 = OK -1 = unacceptable date (Note 1) Notes: 1) The earliest valid date is -68569.5 (-4900 March 1). The largest value accepted is 1e9. 2) The Julian Date is apportioned in any convenient way between the arguments dj1 and dj2. For example, JD=2450123.7 could be expressed in any of these ways, among others: dj1 dj2 2450123.7 0.0 (JD method) 2451545.0 -1421.3 (J2000 method) 2400000.5 50123.2 (MJD method) 2450123.5 0.2 (date & time method) Separating integer and fraction uses the "compensated summation" algorithm of Kahan-Neumaier to preserve as much precision as possible irrespective of the jd1+jd2 apportionment. 3) In early eras the conversion is from the "proleptic Gregorian calendar"; no account is taken of the date(s) of adoption of the Gregorian calendar, nor is the AD/BC numbering convention observed. References: Explanatory Supplement to the Astronomical Almanac, P. Kenneth Seidelmann (ed), University Science Books (1992), Section 12.92 (p604). Klein, A., A Generalized Kahan-Babuska-Summation-Algorithm. Computing, 76, 279-293 (2006), Section 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.