Messier 6
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| The Messier Butterfly Cluster 6 amateur shot. | |
| AladinLite | |
| Constellation | Scorpio |
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Position equinox : J2000.0 |
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|---|---|
| Right ascension | 17 h 40 m 18 s |
| declination | −32 ° 12 ′ |
| Appearance
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| classification | II 3 r |
| Brightness (visual) | +4.2 mag |
| Angular expansion | 33 ' |
| Number of stars | about 80 |
| Brightest star | BM Scorpii , +6.17 mag |
| Variable stars |
BM Scorpii V862 Scorpii |
| Redness ( excess color E (BV)) | 0.144 mag |
| Physical data
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| distance | approx. 1,600 ly |
| diameter | approx. 12 ly |
| Age | approx. 100 million years |
| Metallicity [Fe / H] | +0.06 |
| history | |
| Discovered by | Giovanni Battista Hodierna |
| Discovery time | around 1654 |
| Catalog names | |
| M 6 • NGC 6405 • C 1736-321 • OCl 1030 • Mel 178 • Cr 341 • Lund 769 • ESO 455-SC030 • GC 4318 • Lac III 12 • h 3699 | |
Messier 6 (also known as NGC 6405 ) is a 4.2 mag bright open star cluster in the eastern part of the constellation Scorpio , north of Lesath . The star cluster has an apparent dimension of 33 'and is around 1,600 light years from Earth . Messier 6 was already known in ancient times and is sometimes referred to as the butterfly cluster. It is difficult to see in Central Europe , but a noticeable object in southern latitudes.
discovery
The open star cluster was discovered in the period before 1654 by the Italian astronomer Giovanni Battista Hodierna . It is assumed that Claudius Ptolemy could already have seen Messier 6 while observing Messier 7 ; however, this is not certain. Independently of this, the Swiss Jean-Philippe de Chéseaux observed Messier 6 in 1745 or 1746. Nicolas Louis de Lacaille gave him the name Lac III 12, who observed him in 1752 at the Cape of Good Hope . Charles Messier finally observed him on May 23, 1764 and assigned it the number 6 in his catalog.
Web links
- M6 at SEDS
- Spektrum.de : Amateur recordings [1]
- Spektrum.de: Labeled environment photo