Dark Side of the Moon Tour – A Piece for Assorted Lunatics", the name under which it made its press debut in February 1972 at London's Rainbow Theatre. The title changed for the first part of the US tour to "Eclipse (A Piece for Assorted Lunatics)" during April and May before reverting to "Dark Side of the Moon – A Piece for Assorted Lunatics" in September for the second part of the US tour and finally released in 1973 under the title of "The Dark Side of the Moon". Remarkably, at its first full live performance at Guildhall, Portsmouth, England on 21 January 1972, most of
Orbit of the Moon orbit of the Moon is distinctly elliptical, with an average eccentricity of 0.0549. The non-circular form of the lunar orbit causes variations in the Moon's angular speed and apparent size as it moves towards and away from an observer on Earth. The mean angular movement relative to an imaginary observer at the Earth-Moon barycentre is ° per day to the east (Julian day 2000). The Moon's elongation is its angular distance east of the Sun at any time. At new moon, it is zero and the Moon is said to be in conjunction. At full moon, the elongation is 180°