Fact sheet
- Latin name
- Telescopium (Tel)
- Brightest star
- α Telescopii (α Tel)
- Relative brightness
- 3.51 mag
- Hipparcos catalogue
- HIP 90422
- Area
- 252 deg² (rank: 57 out of 88)
- Right ascension
- 18h 09m 14s to 20h 29m 50s
- Declination
- -56° 59' 02'' to -45° 05' 24''
- Neighbouring constellations
- Sagittarius, Corona Australis, Ara, Pavo, Indus
Visibility
The constellation Telescopium
Telescopium is a constellation of the southern hemisphere. Its brightest star is α Telescopii, a bluish star that is around 800 times as luminous as our sun. However, because this star is 278 light years away from us (1 light year is 9.461 trillion kilometres), it is harder to see than our sun at a distance of 149.6 million km. Telescopium lies north of the constellation Pavo and south of Sagittarius.
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.
The telescope was a ground-breaking invention for astronomers. So it is not surprising that Nicolas-Louis de Lacaille dedicated a constellation of its own to it. In it, he immortalised the Keplerian telescope, which follows a design described by Johannes Kepler in 1611. However, when Nicolas-Louis de Lacaille introduced the constellation, it still had two more stars of the 3rd magnitude, which today no longer belong to the constellation Telescopium. β Telescopii is now called η Sagittarii and belongs to the constellation Sagittarius, and γ Telescopii is now G Scorpii in the constellation Scorpius.
