jday: Calculates the astronomical Julian day

In ilyamaclean/microctools: Various worker functions for microclimc package

Calculates the astronomical Julian day

Description

jday is used to calculate the astronomical Julian day (days since since January 1, 4713 BCE at noon UTC) from a given year, month and day.

Usage

jday(year, month, day, hour = 12, min = 0, sec = 0, dst = 0, tme = NA)

Arguments

year	year (AD).
month	month in numeric form (1-12).
day	days of the month (1-31).
hour	hours (decimal, 0-23).
min	minutes (decimal, 0-59).
sec	seconds (decimal, 0-59).
dst	an optional numeric value specifying the time zone expressed as hours different from GMT (-ve to west).
tme	POSIXlt object of times in UTC. Other inputs ignored if this is provided

Value

Julian Day. I.e. the number of days since January 1, 4713 BCE at noon UTC.

Examples

tme <- as.POSIXlt(0, origin = "2020-03-21 12:43", tz = "UTC")
jday(tme = tme)
jd1 <- jday(2010, 1, 31)
jd2 <- jday(2010, 1, 31, 11, 0, 0)
jd1 - jd2

ilyamaclean/microctools documentation built on Jan. 25, 2023, 5:29 a.m.