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
Full moon is called a blue moon. The term "blue moon" used in this sense may date to as early as the 16th century, but it became well known in the United States due to the "Farmers' Almanac" (published since 1818). According to the "Farmers' Almanac", a "blue moon" is the third full moon in any period between either solstice and equinox, or between equinox and solstice, (calculated using the mean tropical year), which contains four full moons. These seasons are equal in length, unlike the astronomical ones, which vary in length depending on the Earth's speed in its elliptical orbit round