Convert 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
geocentric latitude, in degrees
obliquity of the ecliptic, in degrees
A data frame containing columns
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, 1982. Astronomical formulae for Calculators. Willmann-Bell. Richmond VA, USA. 201 pages.
Meeus, Jean, 1991. Astronomical algorithms. Willmann-Bell, Richmond VA, USA. 429 pages.