History: Mensa is not a classical constellation, but rather was first described by Abbe Nicholaus de Lacaille, who described the Southern Celestial Sphere between the years 1751 through 1753. Originally, it was cataloged as Mons Mensae ("Table Mountain"), an actual mountain near Cape Town in South Africa. De Lacaille made his observations of the Southern Hemisphere sky from the Cape of Good Hope near Cape Town, but in the centuries that followed "Mons" ("Mountain") was dropped from its name. Because it is a newer constellation, there is no classical mythology associated with this figure.
Other Interesting Sights: The Large Magellanic Cloud is within this constellation. The Large and Small Magellanic Clouds were first described by Ferdinand Magellan in 1519 and are satellite galaxies to our own Milky Way Galaxy, approximately 160,000 light years away. The Magellanic Clouds are actually spread out over three constellations -- Dorado, Tucana, and Mensa. Within the Large Magellanic Cloud is the fascinating Tarantula Nebula, also called the True Lovers' Knot (NGC2070). This nebula is intriguing because it is the only extragalactic nebula visible to the naked eye.
The Large Magellanic Cloud
The Tarantula Nebula, NGC2070
(Photos copyright of: Anglo-Australian Telescope Board;
Taken by the UK Schmidt Telescope, David Malin.)