View source for Science:Erfa:eraCal2jd

=== eraCal2jd ===

<code>int eraCal2jd(int iy, int im, int id, double *djm0, double *djm)</code>

Gregorian Calendar to Julian Date.

Given:
* iy,im,id: int: year, month, day in Gregorian calendar (Note 1)

Returned:
* djm0: double: MJD zero−point: always 2400000.5
* djm: double: Modified Julian Date for 0 hrs

Returned (function value): int status:
* 0 = OK
* −1 = bad year (Note 3: JD not computed)
* −2 = bad month (JD not computed)
* −3 = bad day (JD computed)

Notes:

1) The algorithm used is valid from −4800 March 1, but this implementation rejects dates before −4799 January 1.

2) The Julian Date is returned in two pieces, in the usual ERFA manner, which is designed to preserve time resolution. The Julian Date is available as a single number by adding djm0 and djm.

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.

Reference:

Explanatory Supplement to the Astronomical Almanac, P. Kenneth Seidelmann (ed), University Science Books (1992), Section 12.92 (p604).

Copyright (C) 2013−2018, NumFOCUS Foundation. Derived, with permission, from the SOFA library. See notes at end of file.