One of the fourteen constellations created in the 18th century by French astronomer Nicolas-Louis de Lacaille, Mensa is in the Southern Celestial Hemisphere close to the South Celestial Pole. Although it originally honoured Table Mountain and was called "Mons Mensae," its name is Latin for "table." It is one of the eighty-eight constellations recognised by the International Astronomical Union (IAU) and occupies a wedge-shaped region of the sky measuring 153.5 square degrees. It is the most southerly of the constellations, other than the south pole constellation of Octans, and is only visible south of the fifth parallel of the Northern Hemisphere.
Mensa is one of the lightest constellations in the night sky; the brightest star, Alpha Mensae, is scarcely visible in suburban skies. Mensa does not appear to have any brilliant stars. The region occupied by the constellation contains a quasar, many star clusters, and a portion of the Large Magellanic Cloud. At least three of its star systems have been discovered to have exoplanets. |
History
Mensa was made by Nicolas-Louis de Lacaille out of faint Southern Hemisphere stars in honour of Table Mountain, a South African mountain overlooking Cape Town, close to the location of Lacaille's observatory. It was originally called "Montagne de la Table" or "Mons Mensae". He noted that when a stormy south-easterly wind blew, Table Mountain was frequently enveloped in clouds and that the Magellanic Clouds were sometimes referred to as Cape clouds. Therefore, he created a "table" in the clouds of the sky. (Wagman 2003) During his two years near the Cape of Good Hope, Lacaille viewed and recorded 10,000 southern stars. In unexplored areas of the Southern Celestial Hemisphere that were obscured from Europe, he created fourteen new constellations. The only constellation that did not commemorate a tool associated with the Age of Enlightenment was Mensa. (Wagman 2003) Sir John Herschel suggested condensing the name to a single word in 1844, pointing out that Lacaille had done the same with some of his constellations. (Herschel 1844)
The mountain for which Mensa is named has a rich mythology, even though the stars of Mensa are not mentioned in any ancient myths. Its neighbours, the mountains known as "Devil's Peak" and "Lion's Head," are termed "Tafelberg" in both Dutch and German. The folklore surrounding the storm-prone Cape of Good Hope includes Table Mountain. Bartolomeu Dias, an explorer, thought of the peak as a storm's mythical anvil.
Mensa was made by Nicolas-Louis de Lacaille out of faint Southern Hemisphere stars in honour of Table Mountain, a South African mountain overlooking Cape Town, close to the location of Lacaille's observatory. It was originally called "Montagne de la Table" or "Mons Mensae". He noted that when a stormy south-easterly wind blew, Table Mountain was frequently enveloped in clouds and that the Magellanic Clouds were sometimes referred to as Cape clouds. Therefore, he created a "table" in the clouds of the sky. (Wagman 2003) During his two years near the Cape of Good Hope, Lacaille viewed and recorded 10,000 southern stars. In unexplored areas of the Southern Celestial Hemisphere that were obscured from Europe, he created fourteen new constellations. The only constellation that did not commemorate a tool associated with the Age of Enlightenment was Mensa. (Wagman 2003) Sir John Herschel suggested condensing the name to a single word in 1844, pointing out that Lacaille had done the same with some of his constellations. (Herschel 1844)
The mountain for which Mensa is named has a rich mythology, even though the stars of Mensa are not mentioned in any ancient myths. Its neighbours, the mountains known as "Devil's Peak" and "Lion's Head," are termed "Tafelberg" in both Dutch and German. The folklore surrounding the storm-prone Cape of Good Hope includes Table Mountain. Bartolomeu Dias, an explorer, thought of the peak as a storm's mythical anvil.
Characteristics
Dorado is Mensa's northern neighbour, followed by Hydrus to its northwest and western edges, Octans to its south, Chamaeleon to its east, and Volans to its northeast. It ranks 75th in size out of eighty-eight constellations, taking up 153.5 square degrees or 0.372 percent of the night sky. "Men" is the three-letter acronym for the constellation that was chosen by the IAU in 1922. (Russell 1922) A polygon with eight segments defines the recognised constellation limits, which were established by Belgian astronomer Eugène Delporte in 1930. These borders' right ascension coordinates in the equatorial coordinate system range from 03h 12m 55.9008s to 07h 36m 51.5289s, while their declination coordinates fall between 69.75° and 85.26°. Observers south of latitude 5°N can see the entire constellation.
Deep-sky Objects
Large Magellanic Cloud is partially situated in Mensa (Tirion 2012)
NGC 1987 – Globular Cluster
NGC 1848 – Open Cluster
IC 2051 – Spiral Galaxy
Main stars - 4
Bayer stars - 16
Stars with planets - 3
Stars brighter than magnitude 3.00 - 0
Stars within 32 Ly - 0
Bordering
constellations
Dorado is Mensa's northern neighbour, followed by Hydrus to its northwest and western edges, Octans to its south, Chamaeleon to its east, and Volans to its northeast. It ranks 75th in size out of eighty-eight constellations, taking up 153.5 square degrees or 0.372 percent of the night sky. "Men" is the three-letter acronym for the constellation that was chosen by the IAU in 1922. (Russell 1922) A polygon with eight segments defines the recognised constellation limits, which were established by Belgian astronomer Eugène Delporte in 1930. These borders' right ascension coordinates in the equatorial coordinate system range from 03h 12m 55.9008s to 07h 36m 51.5289s, while their declination coordinates fall between 69.75° and 85.26°. Observers south of latitude 5°N can see the entire constellation.
Deep-sky Objects
Large Magellanic Cloud is partially situated in Mensa (Tirion 2012)
NGC 1987 – Globular Cluster
NGC 1848 – Open Cluster
IC 2051 – Spiral Galaxy
Main stars - 4
Bayer stars - 16
Stars with planets - 3
Stars brighter than magnitude 3.00 - 0
Stars within 32 Ly - 0
Bordering
constellations
- Chamaeleon
- Dorado
- Hydrus
- Octans
- Volans