astro::rise_set::BodyProvider Concept Reference

A body position provider: apparent equatorial coordinates at one instant. More...

#include <rise_set.hpp>

Concept definition

template<typename P>
concept astro::rise_set::BodyProvider =  std::invocable<const P&, double>
                   and std::convertible_to<std::invoke_result_t<const P&, double>, astro::coords::EquatorialCoord>

Detailed Description

A body position provider: apparent equatorial coordinates at one instant.

Note

The instant is a julian ephemeris day on the TT scale. This is the single seam through which the engine sees a body; per-body sub-namespaces supply the providers.