calendar2jdn {jcalendaR}

jdn

Description

Functions for calculating Julian Date from Gregorian or Julian Date Number and functions for calculating Gregorian or Julian Date from Julian Date Number.

Usage

calendar2jdn(date, jdn = c("jdn", "mjd"), calendar = c("gregorian", "julian"))

jdn2calendar(
  n,
  jdn = c("jdn", "mjd"),
  calendar = c("gregorian", "julian"),
  sep = "/"
)

Arguments

date

Date to be converted. It should always include the year, month, and day.

jdn

Select Julius Date Number or Modified Julius Date Number.

calendar

Select whether the calendar is Gregorian or Julian.

n

Julian Date Number or Modified Julian Date Number value.

sep

The way the date is separated when the last date is written.

Value

* 'jdn2calendar' returns a string type date.

* 'calendar2jdn' returns a a numeric vector.

References

Julian Day Number - Wikipedia [ja] (JD, https://ja.wikipedia.org/wiki/%E3%83%A6%E3%83%AA%E3%82%A6%E3%82%B9%E9%80%9A%E6%97%A5)

Fliegel, H. F., Van Flandern, T. C. (1968), doi:10.1145/364096.364097, "A Machine Algorithm for Processing Calendar Dates", Communications of the ACM 11, p. 657.

Hatcher, D. A. (1984, BibCode:1984QJRAS..25...53H) "Simple formulae for Julian day numbers and calendar dates, Quarterly Journal of the Royal Astronomical Society", v. 25, p. 53-55, https://adsabs.harvard.edu/full/1984QJRAS..25...53H.

Meeus, J. (1998, ISBN:0943396638) "Astronomical Algorithms. Willmann-Bell", Second English Edition.

Examples

jdn2calendar(2459216)
calendar2jdn("2021/1/1")