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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.
Telescopium is bordered by Sagittarius and Corona Australis to the north, Ara to the west, Pavo to the south, and Indus to the east, cornering on Microscopium to the northeast. In the equatorial coordinate system, the right ascension coordinates of the constellation between 18h 09.1m and 20h 29.5m, while the declination coordinates are between −45.09° and −56.98°. The whole constellation is visible to observers south of latitude 33°N.
Telescopium, shown under the name Tubus Astronomicus on Chart XV of the Uranographia by Johann Bode (1801), was envisaged as a long-tubed refractor operated by ropes and pulleys.
[http://www.ianridpath.com/startales/telescopium.htm]
Telescopium was introduced in 1751–52 by Nicolas-Louis de Lacaille with the French name le Telescope, depicting an aerial telescope, 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. Covering 40 degrees of the night sky, the telescope stretched out northwards between Sagittarius and Scorpius. Lacaille had Latinized its name to Telescopium by 1763.
The constellation was known by other names. It was called Tubus Astronomicus in the eighteenth century, during which time three constellations depicting telescopes were recognized- 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. 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. The much-reduced constellation lost several brighter stars to neighbouring constellations.
[http://www.dibonsmith.com/graphs_SH.htm]
Telescopium (Latin: telescope) is a minor southern constellation identified and named by Nicolas Louis de Lacaille, the 18th century French astronomer, a student of the southern skies. Since it was introduced in the 17th century, and, as a southern constellation, was not visible to Mediterranean culture, there is no earlier mythology associated with it.
[http://www.starrynightphotos.com/constellations/telescopium.htm]
Alpha Telescopii is the brightest star in the constellation Telescopium, with an apparent visual magnitude of 3.5. It is 278 light-years (85 parsecs) distant from Earth. This star is much larger than the Sun, with an estimated 5.2±0.4 times the mass and 3.3±0.5 times the radius. The spectrum of the star matches a stellar classification of B3 IV, where the luminosity class of ‘IV’ indicates this is a subgiant star that has nearly exhausted the supply of hydrogen at its core and is evolving away from the main sequence. It is a bright star that is radiating nearly 800 times the Sun’s luminosity. This energy is being emitted from the star’s outer envelope at an effective temperature of around 16,700 K, giving it the characteristic blue-white hue of a B-type star.
[https://en.wikipedia.org/wiki/Alpha_Telescopii]
Zeta Telescopii is the second brightest star in the constellation Telescopium. An orange K-type giant of spectral type K1III-IV, with an apparent magnitude of +4.13 and surface temperature of 4720 K, it is around 1.53 times as massive as the Sun and shining with around 512 times its luminosity. It is approximately 127 light years from Earth.
[https://en.wikipedia.org/wiki/Zeta_Telescopii]
Epsilon Telescopii is a binary star, approximately 420 light years from Earth. The primary component, Epsilon Telescopii A, is an orange K-type giant with an apparent magnitude of +4.52. It has a 13th magnitude companion, Epsilon Telescopii B, 21 arcseconds away from the primary.
[https://en.wikipedia.org/wiki/Epsilon_Telescopii]
Close by Alpha Telescopii are the two blue-white stars sharing the designation of Delta Telescopii. Delta1 Telescopii is of spectral type B6IV and apparent magnitude 4.9, while Delta2 Telescopii is of spectral type B3III and magnitude 5.1. They form an optical double, as the stars are estimated to be around 710 and 1190 light-years away respectively.
The faint (magnitude 12.23) Gliese 754, a red dwarf of spectral type M4.5V, is one of the nearest 100 stars to Earth at 19.3 light-years distant. Its eccentric orbit around the Galaxy indicates that it may have originated in the Milky Way’s thick disk.
NGC 6584
NGC 6584 is a globular cluster in the constellation Telescopium that lies near Theta Arae and is 45,000 light-years distant. It contains at least 69 variable stars, most of which are RR Lyrae variables. The cluster is about 4 kpc from the Galactic center, and about 2.7 kpc from the Galactic plane.
[https://en.wikipedia.org/wiki/NGC_6584]
NGC 6861 is a lenticular galaxy located in the constellation Telescopium. It is the second-brightest object in the constellation. Unlike most lenticular galaxies, which tend to be mostly devoid of both gas and dust, NGC 6861 exhibits a thick obscuring ring of dust around the nucleus where star formation is occurring. The galaxy was discovered by Scottish astronomer James Dunlop, in 1826. NGC 6861 is interacting with NGC 6868, and it is predicted that they will eventually merge:
[https://en.wikipedia.org/wiki/NGC_6861]
The third way of galaxies
The subject of this image is NGC 6861, a galaxy discovered in 1826 by the Scottish astronomer James Dunlop. Almost two centuries later we now know that NGC 6861 is the second brightest member of a group of at least a dozen galaxies called the Telescopium Group- otherwise known as the NGC 6868 Group- in the small constellation of Telescopium (The Telescope).
This NASA/ESA Hubble Space Telescope view shows some important details of NGC 6861. One of the most prominent features is the disc of dark bands circling the center of the galaxy. These dust lanes are a result of large clouds of dust particles obscuring the light emitted by the stars behind them.
Dust lanes are very useful for working out whether we are seeing the galaxy disc edge-on, face-on or, as is the case for NGC 6861, somewhat in the middle. Dust lanes like these are typical of a spiral galaxy. The dust lanes are embedded in a white oval shape, which is made up of huge numbers of stars orbiting the center of the galaxy. This oval is, rather puzzlingly, typical of an elliptical galaxy.
So which is it- spiral or elliptical? The answer is neither! NGC 6861 does not belong to either the spiral or the elliptical family of galaxies. It is a lenticular galaxy, a family which has features of both spirals and ellipticals.
The relationships between these three kinds of galaxies are not yet well understood. A lenticular galaxy could be a faded spiral that has run out of gas and lost its arms, or the result of two galaxies merging. Being part of a group increases the chances for galactic mergers, so this could be the case for NGC 6861.
[https://www.spacetelescope.org/images/potw1502a/]
NGC 6845 in Telescopium
[http://www.capella-observatory.com/ImageHTMLs/Galaxies/NGC6845.htm]
NGC 6845 (also known as Klemola 30) is an interacting system of four galaxies in the constellation Telescopium. The cluster has certain similarities with Stephan’s Quintet. Its distance is estimated to be about 90 Mpc. The components of the galaxy cluster are the two spiral galaxies NGC 6845A and NGC 6845B as well as the two lenticular galaxies NGC 6845C and NGC 6845D. The four galaxies occupy an area of about 4' x 2' in the sky. The largest galaxy in this compact galaxy cluster is NGC 6845A, a barred spiral galaxy.NGC 6845 was discovered on July 7, 1834 by John Herschel.
[https://en.wikipedia.org/wiki/NGC_6845]
SN 1998bw
SN 1998bw was a rare broad-lined Type Ic gamma ray burst supernova detected on 26 April 1998 in the ESO 184-G82 spiral galaxy, which some astronomers believe may be an example of a collapsar (Hypernova). The supernova has been linked to GRB 980425, which was detected on 25 April 1998, the first time a gamma-ray burst has been linked to a supernova. The supernova is approximately 140 million light years away, very close for a gamma ray burst source.
The region of the galaxy where the supernova occurred hosts stars 5-8 million years old and is relatively free from dust. A nearby region hosts multiple Wolf-Rayet stars less than 3 million years old, but it is unlikely that the supernova progenitor could be a runaway from that region. The implication is that the progenitor was a star originally 25-40 M☉ if it exploded as a single star at the end of its life.
[https://en.wikipedia.org/wiki/SN_1998bw]
[https://en.wikipedia.org/wiki/Telescopium]
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