Fact sheet
- Latin name
- Mensa (Men)
- Brightest star
- α Mensae (α Men)
- Relative brightness
- 5.09 mag
- Hipparcos catalogue
- HIP 29271
- Area
- 153 deg² (rank: 75 out of 88)
- Right ascension
- 3h 12m 56s to 7h 36m 52s
- Declination
- -85° 15' 41'' to -69° 44' 48''
- Neighbouring constellations
- Dorado, Hydrus, Octans, Chamaeleon, Volans
Visibility
The constellation Mensa
Mensa is a constellation of the southern hemisphere. It is circumpolar around the South Pole. This means that its stars are so close to the celestial pole that they never set as seen from Sydney. The constellation is therefore above the horizon all year round there. Its brightest star is α Mensae, which has an apparent magnitude of only 5.09 mag. It can only be seen with the naked eye under good conditions. Mensa is the faintest constellation in the sky. The Large Magellanic Cloud (LMC), a dwarf galaxy about 160,000 light years away with many billions of stars, helps to find this constellation. A small part of the Large Magellanic Cloud extends into the constellation Mensa. However, most of it lies in the constellation Dorado.
History
The French theologian Nicolas-Louis de Lacaille, who devoted his life to astronomy, geodesy and mathematics, introduced 14 new constellations of the southern hemisphere. In 1750, he set off on a four-year journey to the Cape of Good Hope in order to observe, among other things, the constellations of the southern sky. During this time, he catalogued almost 10,000 stars. Nicolas-Louis de Lacaille named most of his new constellations after technical instruments. In this way, the constellations Sculptor, Fornax, Caelum, Antlia, Pictor, Microscopium, Reticulum, Octans, Horologium, Pyxis, Mensa, Telescopium, Norma and Circinus came into being. He also divided the large ancient constellation Argo Navis into the three constellations Carina, Puppis and Vela. His star catalogue of the southern sky was published in 1763, one year after his death, under the title “Coelum Australe Stelliferum”. What his 14 new constellations have in common is that they consist of relatively faint stars.
Nicolas-Louis de Lacaille studied the stars of the southern sky from Cape Town and immortalised Table Mountain, with the clouds lying above it, in the constellation Mensa. The natural spectacle around Table Mountain can best be admired in the South African summer (in December). At this time, a thin layer of cloud lies over the mountain and seems to flow down the steep slopes on the north and west sides. The local people call this phenomenon the “tablecloth”.
