Orbit of the Moon the perigee and apogee, respectively – makes one complete revolution every 8.85 Earth years, or 3,232.6054 days, as it rotates slowly in the same direction as the Moon itself (direct motion). The Moon's apsidal precession is distinct from the nodal precession of its orbital plane and axial precession of moon itself. The mean inclination of the lunar orbit to the ecliptic plane is 5.145°. Theoretical considerations show that the present inclination relative to the ecliptic plane arose by tidal evolution from an earlier near-Earth orbit with a fairly constant inclination relative to Earth's equator. It would require an inclination of
Near-Earth object smaller than about in diameter (i.e. H = 22.0 with assumed albedo of 14%), are not considered PHAs. NASA's catalog of near-Earth objects also includes the approach distances of asteroids and comets (expressed in lunar distances). The first near-Earth objects to be observed by humans were comets. Their extraterrestrial nature was recognised and confirmed only after Tycho Brahe tried to measure the distance of a comet through its parallax in 1577; and the periodicity of some comets was recognised in 1705, when Edmond Halley first published his orbit calculations for the returning object now known as Halley's Comet. The 1758–1759