# Julian Day Number from Date Calculator

## Calculates Julian Day and Modified Julian Day numbers from Julian and Gregorian calendars.

 The Julian Day number is the number of days elapsed since noon (12:00) on January 1, 4713 BCThe Modified Julian Day number is the number of days since midnight (00:00) on November 17, 1858 AD (MJD=JD-2400000.5)The Gregorian calendar is used for dates on and after October 15, 1582 AD and the Julian calendar is used before October 4, 1582.
Julian Day Number from Date
 [1-10] /19 Disp-Num5103050100200
[1]  2022/07/08 06:24   60 years old level or over / A retired person / Useful /
Purpose of use
Exploring usage and history of Julian days as used in astronomy.
[2]  2022/01/18 07:21   Under 20 years old / High-school/ University/ Grad student / Very /
Purpose of use
To check my work for a matlab class I am taking right now.
[3]  2020/10/14 19:21   50 years old level / An engineer / Very /
Purpose of use
To check my own build Julian Day Calculator. (It is actually very easy done with Python!)
[4]  2020/10/14 15:46   60 years old level or over / A retired person / Useful /
Purpose of use
To check my theory that I was effectively 70 years old when I had a celebratory lunch for my birthday on the 11th October 2020 instead of the following day, the 12th, which is the day on my birth certificate.

Comment/Request
Seems to work well...
[5]  2020/04/23 05:24   60 years old level or over / An engineer / Very /
Purpose of use
Doing automated maintenance on log files and related purging.
[6]  2020/04/04 21:41   60 years old level or over / A retired person / Useful /
Purpose of use
To check the Julian day number on the day of the full moon this April from the full moon in
[7]  2020/03/14 16:13   50 years old level / Self-employed people / Very /
Purpose of use
I wrote a calendar application which displays Roman calendars, Mayan Long Count and Tzol'kin Haab', and the Julian Day number (as if JDN 0 began at 0h). Useful resource.
[8]  2020/03/14 14:32   50 years old level / Self-employed people / Very /
Purpose of use
I wrote a calendar application which displays Roman calendars, Mayan Long Count and Tzol'kin Haab', and the Julian Day number (as if JDN 0 began at 0h). Useful resource.
[9]  2020/02/14 19:47   60 years old level or over / A retired person / A little /
Purpose of use
check other programs
Comment/Request
the starting point of MJD is ambiguous. midnight is 0h or 24h? should be 0h

the JD value xxx.5 should refer to 0h of the given day. this should be stated.
[10]  2020/01/06 05:53   Under 20 years old / High-school/ University/ Grad student / Useful /
Purpose of use
Needed Modified Julian Day for a cipher conversion system.

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