Horologium is a Southern Hemisphere constellation otherwise known as the Clock. It is one of fourteen new constellations created by French astronomer Abbe Nicolas Louis de Lacaille (Wikipedia) in the 1750s, from his star catalog observations from the Cape of Good Hope and published posthumously in Coelum Australe Stelliferum in 1763. Horologium remains one of the 88 modern constellations defined by the International Astronomical Union (Wikipedia).
Horologium (abbrev. = Hor; genitive = Horologii) covers 249 square degrees or 0.60% of the celestial sphere making it the 58th largest constellation. It contains 30 stars brighter than apparent magnitude 6.5, the brightest star being Alpha Horologii.