 Musca is bordered by Crux to the north, Carina to the west, Chamaeleon to the south, Apus and Circinus to the east and Centaurus to the northeast. Covering 138 square degrees and 0.335 % of the night sky, it ranks 77th of the 88 constellations in size. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is'Mus'. The official constellation boundaries, as set by Eugène Delporte in 1930, are defined by a polygon of six segments. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 11h 19.3m and 13h 51.1m, while the declination coordinates are between − 64.64°and − 75.68 °. The whole constellation is visible to observers south of latitude 14°N.
