where did the blue moon get its name
Blue moon The term has traditionally referred to an "extra" moon, where a year which normally has 12 moons has 13 instead. The "blue moon" reference is applied to the third moon in a season with four moons,[2] thus correcting the timing of the last month of a season that would have otherwise been expected too early. This happens every two to three years (seven times in the Metonic cycle of 19 years).[3] The March 1946 issue of Sky & Telescope misinterpreted the traditional definition, which led to the modern colloquial misunderstanding that a blue moon is a second full moon in a single solar calendar month with no seasonal link.
Blue Mountains (New South Wales) Following European settlement of the Sydney area, the area was named the Carmarthen and Lansdowne Hills by Arthur Phillip in 1788. The Carmarthen Hills were in the north of the region and the Lansdowne Hills were in the south. The name Blue Mountains, however, was preferred[8] and is derived from the blue tinge the range takes on when viewed from a distance. The tinge is believed to be caused by Mie scattering which occurs when incoming light with shorter wavelengths is preferentially scattered by particles within the atmosphere creating a blue-greyish colour to any distant objects, including mountains and clouds. Volatile terpenoids emitted in large quantities by the abundant eucalyptus trees in the Blue Mountains may cause Mie scattering and thus the blue haze for which the mountains were named.[9]