| sunDeclinationRightAscension {oce} | R Documentation |
The formulae are from Meeus (1991), chapter 24 (which uses chapter 21).
sunDeclinationRightAscension(time, apparent = FALSE)
time |
a POSIXct time. This ought to be in UTC timezone; if not, the behaviour of this function is unlikely to be correct. |
apparent |
logical value indicating whether to return the 'apparent' angles. |
A list containing declination and rightAscension, in degrees.
Dan Kelley, based on formulae in Meeus (1991).
Meeus, Jean H. Astronomical Algorithms. Second edition. Willmann-Bell, Incorporated, 1991.
Other things related to astronomy:
eclipticalToEquatorial(),
equatorialToLocalHorizontal(),
julianCenturyAnomaly(),
julianDay(),
moonAngle(),
siderealTime(),
sunAngle()
## Example 24.a in Meeus (1991) (page 158 PDF, 153 print)
time <- as.POSIXct("1992-10-13 00:00:00", tz="UTC")
a <- sunDeclinationRightAscension(time, apparent=TRUE)
expect_equal(a$declination, -7.78507,
tol= 0.00004, scale=1)
expect_equal(a$rightAscension, -161.61919,
tol= 0.00003, scale=1)
b <- sunDeclinationRightAscension(time)
## check against previous results, to protect aginst code-drift errors
expect_equal(b$declination, -7.785464443,
tol= 0.000000001, scale=1)
expect_equal(b$rightAscension, -161.6183305,
tol= 0.0000001, scale=1)