The formulae are from Meeus (1991), chapter 24 (which uses chapter 21).

sunDeclinationRightAscension(time, apparent = FALSE)

Arguments

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.

Value

A list containing declination and rightAscension, in degrees.

References

  1. Meeus, Jean H. Astronomical Algorithms. Second edition. Willmann-Bell, Incorporated, 1991.

See also

Examples

## 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)