Full moon another full supermoon occurred, closer to the Earth than at any time for the previous 18 years. On 14 November 2016, a full supermoon occurred closer to the Earth than at any time for the previous 68 years. The date and approximate time of a specific full moon (assuming a circular orbit) can be calculated from the following equation: where "d" is the number of days since 1 January 2000 00:00:00 in the Terrestrial Time scale used in astronomical ephemerides; for Universal Time (UT) add the following approximate correction to "d": where "N" is the number of full moons since
Equinox zero. Its latitude will not be exactly zero, since Earth is not exactly in the plane of the ecliptic. Its declination will not be exactly zero either. (The ecliptic is defined by the barycenter of Earth and the Moon combined.) The modern definition of equinox is the instants when the Sun's apparent geocentric longitude is 0° (northward equinox) or 180° (southward equinox). See the adjacent diagram. Because of the precession of the Earth's axis, the position of the vernal point on the celestial sphere changes over time, and the equatorial and the ecliptic coordinate systems change accordingly. Thus when specifying