Examples

Some examples are given below. For more information see https://oneau.wordpress.com/2011/08/30/jdcal/.

Gregorian calendar:

>>> from jdcal import gcal2jd, jd2gcal
>>> gcal2jd(2000,1,1)
(2400000.5, 51544.0)
>>> 2400000.5 + 51544.0 + 0.5
2451545.0

>>> gcal2jd(2000,2,30)
(2400000.5, 51604.0)
>>> gcal2jd(2000,3,1)
(2400000.5, 51604.0)
>>> gcal2jd(2001,2,30)
(2400000.5, 51970.0)
>>> gcal2jd(2001,3,2)
(2400000.5, 51970.0)

>>> jd2gcal(*gcal2jd(2000,1,1))
(2000, 1, 1, 0.0)
>>> jd2gcal(*gcal2jd(1950,1,1))
(1950, 1, 1, 0.0)

>>> gcal2jd(2000,1,1)
(2400000.5, 51544.0)
>>> jd2gcal(2400000.5, 51544.0)
(2000, 1, 1, 0.0)
>>> jd2gcal(2400000.5, 51544.5)
(2000, 1, 1, 0.5)
>>> jd2gcal(2400000.5, 51544.245)
(2000, 1, 1, 0.24500000000261934)
>>> jd2gcal(2400000.5, 51544.1)
(2000, 1, 1, 0.099999999998544808)
>>> jd2gcal(2400000.5, 51544.75)
(2000, 1, 1, 0.75)

Julian calendar:

>>> jd2jcal(*jcal2jd(2000, 1, 1))
(2000, 1, 1, 0.0)
>>> jd2jcal(*jcal2jd(-4000, 10, 11))
(-4000, 10, 11, 0.0)

Gregorian leap year:

>>> from jdcal import is_leap
>>> is_leap(2000)
True
>>> is_leap(2100)
False

JD for zero point of MJD, and MJD for JD2000.0:

>>> from jdcal import MJD_0, MJD_JD2000
>>> print MJD_0
2400000.5
>>> print MJD_JD2000
51544.5

Installation

The module can be installed using pip or easy_install:

$ pip install jdcal

or,

$ easy_install jdcal

Tests are in test_jdcal.py.

Credits

1. A good amount of the code is based on the excellent TPM C library by Jeffrey W. Percival.

2. The inspiration to split Julian dates into two numbers came from the IAU SOFA C library. No code or algorithm from the SOFA library is used in jdcal.

License

Released under BSD; see LICENSE.txt.

For comments and suggestions, email to user prasanthhn in the gmail.com domain.