Messier 7
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| Photo of the MPG / ESO 2.2 m telescope | |
| AladinLite | |
| Constellation | Scorpio |
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Position equinox : J2000.0 |
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|---|---|
| Right ascension | 17 h 53.8 m |
| declination | −34 ° 47 ′ |
| Appearance
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| classification | I, 3, m (Trumpler), e (Shapley) |
| Brightness (visual) | 3.3 mag |
| Brightness (B-band) | 3.45 likes |
| Angular expansion | 80 ' |
| Number of stars | 80 that are lighter than 10mag |
| Brightest star | 5.89 likes |
| Physical data
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| Redshift | -47 · 10 -6 |
| Radial velocity | −14.21 km / s |
| distance | 800 ly (250 pc ) |
| diameter | 18–20 years |
| Age | 220 million years |
| history | |
| Discovery time | prehistoric |
| Catalog names | |
| M 7 • NGC 6475 • C 1750-348 • OCl 1028 • Mel 183 • Cr 354 • Lund 791 • ESO 394-SC9 • | |
Messier 7 (also known as NGC 6475 ) is a +3.3 mag bright open star cluster in the eastern part of Scorpio north of Lesath with an extension of 80 '.
The cluster is about 800 light years away towards the galactic center . It consists of around 100 stars and has a diameter of around 25 light years. Its age is estimated to be 200 million years.
In 130 the mathematician and astronomer Claudius Ptolemy was the first to mention this star cluster, which is why it is also called the Ptolemy star cluster . After the Pleiades ( Messier 45 ) and the Praesepe ( Messier 44 ), M 7 is the third brightest star cluster in our sky. It is difficult to see in Central Europe, but a noticeable object in southern latitudes. M7 is the southernmost object in the Messier catalog .
Individual evidence
- ^ NED data for the Messier Objects
- ↑ a b c d e f g Messier 7 at SEDS
- ↑ a b c SIMBAD Astronomical Database
- ↑ http://www.eso.org/public/germany/news/eso1406/
- ↑ SuW 08.2017 p. 60f
Web links
- http://www.eso.org/public/germany/videos/eso1406a/ (zoom on Messier 7)
- Spektrum.de : Amateur recordings [1]
