Convert From POSIXt Time to Sidereal Time

Convert a POSIXt time to a sidereal time, using the method in Chapter 7 of reference 1. The small correction that he discusses after his equation 7.1 is not applied here.

Usage

siderealTime(t)

Arguments

t

a time, in POSIXt format, e.g. as created by as.POSIXct(), as.POSIXlt(), or numberAsPOSIXct(). If this is provided, the other arguments are ignored.

Value

A sidereal time, in hours in the range from 0 to 24.

References

• Meeus, Jean. Astronomical Formulas for Calculators. Second Edition. Richmond, Virginia, USA: Willmann-Bell, 1982.

See also

Other things related to astronomy: angle2hms(), eclipticalToEquatorial(), equatorialToLocalHorizontal(), julianCenturyAnomaly(), julianDay(), moonAngle(), sunAngle(), sunDeclinationRightAscension()

Author

Dan Kelley

Examples

t <- ISOdatetime(1978, 11, 13, 0, 0, 0, tz = "UTC")
print(siderealTime(t))
#> [1] 3.45037