Abbreviation Tel
Genitive Telescopii
Pronunciation əm/,
genitive /
Symbolism the Telescope
Right ascension 19
Declination −50
Quadrant SQ4
Area 252 sq. deg. ( 57th)
Main stars 2
Bayer/ Flamsteed
Stars with planets 0
Stars brighter than 3.00m 0
Stars within 10.00 pc (32.62 ly) 2
Brightest star α Tel (3.49 m)
Messier objects none
Visible at latitudes between + 40° and − 90°.
Best visible at 21:00 (9 p.m.) during the month of August.

Telescopium is a minor constellation in the southern celestial hemisphere, one of twelve named in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. Its name is a Latinized form of the Greek word for telescope. Telescopium was later much reduced in size by Francis Baily and Benjamin Gould.

The brightest star in the constellation is Alpha Telescopii, a blue-white subgiant with an apparent magnitude of 3.5, followed by the orange giant star Zeta Telescopii at magnitude 4.1. Eta and PZ Telescopii are two young star systems with debris disks and brown dwarf companions. Telescopium hosts two unusual stars with very little hydrogen that are likely to be the result of two merged white dwarfs: PV Telescopii, also known as HD 168476, is a hot blue extreme helium star, while RS Telescopii is an R Coronae Borealis variable. RR Telescopii is a cataclysmic variable that brightened as a nova to magnitude 6 in 1948.


Seen in the 1824 star chart set Urania's Mirror (in the lower right)

Telescopium was introduced in 1751–52 by Nicolas-Louis de Lacaille with the French name le Telescope, [1] depicting an aerial telescope, [2] after he had observed and catalogued 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised 14 new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honored instruments that symbolised the Age of Enlightenment. [3] Covering 40 degrees of the night sky, [2] the telescope stretched out northwards between Sagittarius and Scorpius. [4] Lacaille had Latinised its name to Telescopium by 1763. [1]

The constellation was known by other names. It was called Tubus Astronomicus in the eighteenth century, during which time three constellations depicting telescopes were recognised— Tubus Herschelii Major between Gemini and Auriga and Tubus Herschelii Minor between Taurus and Orion, both of which had fallen out of use by the nineteenth century. [5] Johann Bode called it the Astronomische Fernrohr in his 1805 Gestirne and kept its size, but later astronomers Francis Baily and Benjamin Gould subsequently shrank its boundaries. [6] The much-reduced constellation lost several brighter stars to neighbouring constellations: Beta Telescopii became Eta Sagittarii, which it had been before Lacaille placed it in Telescopium, [7] Gamma was placed in Scorpius and renamed G Scorpii by Gould, [7] Theta Telescopii reverted to its old appellation of d Ophiuchi, [7] and Sigma Telescopii was placed in Corona Australis. Initially uncatalogued, the latter is now known as HR 6875. [7] The original object Lacaille had named Eta Telescopii—the open cluster Messier 7—was in what is now Scorpius, and Gould used the Bayer designation for a magnitude 5 star, which he felt warranted a letter. [7]

Other Languages
azərbaycanca: Teleskop (bürc)
Bân-lâm-gú: Tiàu-kiàⁿ-chō
Cymraeg: Telescopium
dansk: Kikkerten
Ελληνικά: Τηλεσκόπιον
español: Telescopium
galego: Telescopium
客家語/Hak-kâ-ngî: Mong-yén-kiang-chho
한국어: 망원경자리
Basa Jawa: Telescopium
Lëtzebuergesch: Telescopium (Stärebild)
മലയാളം: കുഴൽത്തലയൻ
Bahasa Melayu: Teleskop (buruj)
Mìng-dĕ̤ng-ngṳ̄: Uông-uōng-giáng-cô̤
norsk: Teleskopet
norsk nynorsk: Teleskopet
oʻzbekcha/ўзбекча: Teleskop (yulduz turkumi)
português: Telescopium
Simple English: Telescopium
srpskohrvatski / српскохрватски: Teleskop (zviježđe)
svenska: Kikaren
українська: Телескоп (сузір'я)
Winaray: Telescopium
粵語: 望遠鏡座
中文: 望远镜座