Functions
auto	apparent (const double jde) -> toolbox::SphericalCoordinate
	Calculate the apparent geocentric position of the Moon, using truncated ELP2000-82B.
auto	equatorial_horizontal_parallax (const toolbox::DistanceKm &distance) -> toolbox::AngleRad
	Calculate the equatorial horizontal parallax of the Moon.

Variables
constexpr double	EARTH_EQUATORIAL_RADIUS_KM
	Earth's equatorial radius, in kilometers.

Function Documentation

◆ apparent()

auto astro::moon::geocentric_coord::apparent ( const double jde ) ->toolbox::SphericalCoordinate

inlinenodiscard

Calculate the apparent geocentric position of the Moon, using truncated ELP2000-82B.

Parameters

jde	The julian ephemeris day number, which is based on TT.

Returns: The geocentric ecliptic position of the Moon, calculated using truncated ELP2000-82B.

Exceptions

std::invalid_argument	If JDE(TT) is non-finite.
std::runtime_error	If an internal angle cannot be evaluated.

auto astro::moon::geocentric_coord::equatorial_horizontal_parallax ( const toolbox::DistanceKm & distance ) ->toolbox::AngleRad

inlinenodiscard

Calculate the equatorial horizontal parallax of the Moon.

Parameters

distance The geocentric distance of the Moon.

Exceptions

std::invalid_argument if distance is not finite, or is not greater than Earth's equatorial radius.

Note: The guard is the contract, not a reachability claim: the real Moon never comes near, but this is a public function over a Distance<KM> that is open to any value, and asin of an argument above 1 returns a silent NaN rather than failing (#86).

double astro::moon::geocentric_coord::EARTH_EQUATORIAL_RADIUS_KM

inlineconstexpr

Earth's equatorial radius, in kilometers.

See also: Astronomical Algorithms, Jean Meeus, 1998, Chapter 47 – the equatorial horizontal parallax is asin(6378.14 / r), with r the Earth-Moon distance in the same unit.