R/astronomy.R
eclipticalToEquatorial.RdConvert from ecliptical to equatorial coordinates, using equations 8.3 and 8.4 of reference 1, or, equivalently, equations 12.3 and 12.4 of reference 2.
eclipticalToEquatorial(lambda, beta, epsilon)longitude, in degrees, or a data frame containing
lambda, beta, and epsilon, in which case the next to
arguments are ignored
geocentric latitude, in degrees
obliquity of the ecliptic, in degrees
A data frame containing columns rightAscension and
declination both in degrees.
The code is based on reference 1; see moonAngle() for comments on
the differences in formulae found in reference 2. Indeed,
reference 2 is only cited
here in case readers want to check the ideas of the formulae; DK
has found that reference 2 is available to him via his university library
inter-library loan system, whereas he owns a copy of reference 1.
Meeus, Jean. Astronomical Formulas for Calculators. Second Edition. Richmond, Virginia, USA: Willmann-Bell, 1982.
Meeus, Jean. Astronomical Algorithms. Second Edition. Richmond, Virginia, USA: Willmann-Bell, 1991.
Other things related to astronomy:
angle2hms(),
equatorialToLocalHorizontal(),
julianCenturyAnomaly(),
julianDay(),
moonAngle(),
siderealTime(),
sunAngle(),
sunDeclinationRightAscension()