Created
August 23, 2018 13:36
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Calculate from datetime ot JDN
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def dt_to_jdn(dt): | |
"""Convert datetime to Julian Day Number | |
.. warning: Please verify this calculating method | |
This convertion is based on: | |
'Practical Astronomy with your Calculator or Spreadsheet', | |
4th ed., Duffet-Smith and Zwart, 2011. | |
https://en.wikipedia.org/wiki/Julian_day | |
:param dt: datetime to convert. This must be on UTC. | |
:type dt: datetime.datetime | |
:return: Julian Date | |
:Examples: | |
.. code-block:: console | |
import datetime | |
from utils import * | |
dt_to_jdn(datetime.datetime.now()) | |
2458352.5651478795 | |
""" | |
year = dt.year | |
month = dt.month | |
day = dt.day | |
hours = dt.hour | |
min = dt.minute | |
sec = dt.second | |
micro = dt.microsecond | |
if month == 1 or month == 2: | |
year_ = year - 1 | |
month_ = month + 12 | |
else: | |
year_ = year | |
month_ = month | |
if dt > datetime.datetime(1582, 10, 15): | |
A = math.trunc(year_/100) | |
B = 2 - A + math.trunc(A/4) | |
else: | |
B = 0 | |
if year_ < 0: | |
C = math.trunc((365.25 * year_) - 0.75) | |
else: | |
C = math.trunc(365.25 * year_) | |
D = math.trunc(30.6001 * (month_ + 1)) | |
JD = B + C + D + day + 1720994.5 | |
decimal_part = ((hours - 12)/24.) + ((min)/1440.) + ((sec)/86400.) + ((micro)/8.64e10) | |
JDN = JD + decimal_part | |
return JDN |
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