(the Table) is a southern constellation
which was first introduced by Nicolas Louis de Lacaille
under the name Mons Mensae
for "the table mountain"). This specifically refers to Table Mountain
in South Africa
, where Lacaille made important early observations of the southern sky. It contains no bright stars, with Alpha Mensae its brightest star at a barely visible magnitude 5.09, but it does contain part of the Large Magellanic Cloud
(the rest being in Dorado
The constellation covers a keystone-shaped wedge of sky stretching from approximately 4h to 7.5h of right ascension, and -71 to -85.5 degrees of declination. Other than the south polar constellation of Octans, it is the most southerly of constellations. As a result, it is essentially unobservable from the Northern Hemisphere. Besides those already mentioned, its other neighbouring constellations are Chamaeleon, Hydrus and Volans.
The first images taken by the Chandra X-Ray Telescope were of PKS 0637-752, a quasar in Mensa with a large gas jet visible in both optical and x-ray wavelengths.