cal2jd¶

erfa.cal2jd(iy, im, id)[source]¶

Gregorian Calendar to Julian Date.

Parameters:

iyint array
imint array
idint array

Returns:

djm0double array
djmdouble array

Notes

Wraps ERFA function eraCal2jd. The ERFA documentation is:

- - - - - - - - - -
 e r a C a l 2 j d
- - - - - - - - - -

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).

This revision:  2021 May 11

Copyright (C) 2013-2023, NumFOCUS Foundation.
Derived, with permission, from the SOFA library.  See notes at end of file.

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cal2jd¶