Convert a Julian-Day number to a time in julian centuries since noon on January 1, 1900. The method follows reference 1 equation 15.1. The example reproduces the example provided by reference 1 example 15.a, with fractional error 3e-8.
julianCenturyAnomaly(jd)a julian day number, e.g. as given by julianDay().
Julian century since noon on January 1, 1900.
Meeus, Jean. Astronomical Formulas for Calculators. Second Edition. Richmond, Virginia, USA: Willmann-Bell, 1982.
Other things related to astronomy:
angle2hms(),
eclipticalToEquatorial(),
equatorialToLocalHorizontal(),
julianDay(),
moonAngle(),
siderealTime(),
sunAngle(),
sunDeclinationRightAscension()
Other things related to time:
ctimeToSeconds(),
julianDay(),
numberAsHMS(),
numberAsPOSIXct(),
secondsToCtime(),
unabbreviateYear()
t <- ISOdatetime(1978, 11, 13, 4, 35, 0, tz = "UTC")
jca <- julianCenturyAnomaly(julianDay(t))
cat(format(t), "is Julian Century anomaly", format(jca, digits = 8), "\n")
#> 1978-11-13 04:35:00 is Julian Century anomaly 0.78865684