Once in a black moon? This rare celestial event is set for Monday. A monthly black moon only occurs about once every couple of years.
Black moon is a name recently (2016) given to various new moons or absences of them, within a year. It is not a term used in astronomy and no single accepted definition exists. Among the meanings ascribed to it are these: a second new moon that appears in the same month; the third new moon in an astronomical season with four new moons; the absence of a new moon in February; or the absence of a full moon in February.
Tonight, it’s ours to see completely. It is called a Black Moon, and it is a welcome sight for sore eyes.
Although the black moon itself will be invisible, it will create ideal opportunities for stargazing where planets like Venus, Jupiter, Saturn and the galaxies and nebulae will appear to shine brighter among the darker sky