Canes Venatici
- Big Dipper
- Coma Berenices
- Bootes
The hounds, in the jargon Canes Venatici ( from Latin ), is a constellation north of the celestial equator.
Description
The hounds are a little conspicuous constellation below the handle of the Big Dipper ( or below the tail of the Great Bear ). They are formed by the stars α ( Cor Caroli ) and β Canum Venaticorum. Cor Caroli is strikingly bright with an apparent magnitude of 2.90 m
In the hounds are several galaxies and globular clusters, which were included in the Messier catalog.
History
The Hounds were in ancient times not own constellation, but were attributed to the Great Bear. On old pictures the stars α and β as the hounds Chara (Joy) and Asterion be ( the star realms) of the bear keeper shown.
As a separate constellation of the hunting dogs were only introduced from 1690 through the sky atlas of Johannes Hevelius.
The brightest star, α Canum Venaticorum bears the name Cor Caroli (lat. heart of Karl). On the origin of the name, there are two versions.
He should remember the English kings Charles I and Charles II. Charles I was executed in 1649. When his son Charles II ascended the throne in 1660 and thus continued the dynasty of the Stuarts, to the star, according to the Hofphysikers Sir Charles Scarborough have shone particularly bright. The English cartographer Francis Lamb presented the Star in 1673 in a star chart as a crowned heart is and Cor Caroli Regis Martyris called him.
Another source after the court astronomer Edmond Halley Charles II honored on the occasion of 1675 took place the opening of the Observatory Greenwich.
Celestial objects
Stars
β Canum Venaticorum, also called Chara, has an apparent magnitude of 4.26 m. He is only 27 light years away, is of spectral type G0 to.
Double stars
In a telescope α Canum Venaticorum appears as a double star. In 19.4 arcsec spacing a 5.61 m bright star is visible.
The 120 light years distant brighter star α2 CVn is itself a double star. He has a companion that orbits at 5.47 days. However, the stars have such a small distance to each other that they can not be separated with an optical telescope. Only the spectrum exhibits periodic changes. Such systems are called spectroscopic binaries.
Connected with the rounds is a change in the magnetic field and the brightness between 2.84 m and 2.98 m. α2 CVn is the namesake of a group of variable stars, the Alpha-2 Canum - Venaticorum - variables whose characteristic feature are strong magnetic fluctuations.
The star α1 CVn is also a spectroscopic binary.
17 CVn is a triple system 400 light years away. It consists of approximately three equal stars with magnitudes 5.9 and 6.2 and 6.3 belonging to the spectral class F0, B9 and B7. The system can already be resolved with a smaller telescope in single stars.
25 CVn is 200 light years away. The two components are 5.0 and 6.9 m bright and include the spectral types A7 and F0.
Variable Stars
(Also called La Superba ) Y CVn is a semi- regular variable star whose brightness varies with a period of about 157 days between 5.5 m and 6.0 m. He belongs to the spectral class C6 and is a reddish star with a high content of carbon in the outer shell.
Messier and NGC objects
In the hounds are a series of interesting misty objects. A globular star clusters and galaxies took four of the French astronomer and comet hunter Charles Messier in his catalog of nebulous objects ( Messier catalog).
M 3 is a globular cluster about 30,000 light years away, which consists of more than 100.00 Stars. In binoculars it appears as a round misty spot. The cluster is rather compact and can be resolved only in a larger telescope single stars
Below the first pole star of the Big Dipper to find M51, a spiral galaxy about 30 million light-years away, which is also called the Whirlpool Galaxy or Whirlpool Galaxy. The name comes from the fact that you can see wonderful spiral structures in larger telescopes or on long-exposure photographs, reminiscent of a vortex. In binoculars or a small telescope, however, the structures are not discernible; the galaxy appears as a misty patch. In the close vicinity of M 51 we find NGC 5195, a smaller companion galaxy (see below).
M63 is a spiral galaxy 30 million light years away. In binoculars or telescope middle no spiral structures are recognizable.
M 94 is a spiral galaxy 20 million light years away. In the smaller telescope it appears as a round spot. In the larger telescope has a very bright center is visible.
M 106 is a spiral galaxy 30 million light years away. In binoculars and small telescope it appears as an elongated spot. In the larger telescope approaches of spiral arms and dust clouds are visible. M106 was added to our catalog only subsequently by the way not observed by Charles Messier, but.
NGC 4244 is a relatively faint galaxy 20 million light years away.
NGC 4449 is an irregular-shaped, irregular galaxy in 16 million light years away. She looks through the telescope from almost rectangular. In the larger telescope dust structures become visible.
NGC 4490 is a spiral galaxy 40 million light years away. In a telescope it appears extended oblong. In arcmin distance is the smaller companion galaxy NGC 4485, the two galaxies are bound by gravitational forces together and connected by a bridge of matter. ; however this is only seen on long exposure photographs.
NGC 4631 is an elongated spiral galaxy 35 million light years away, which is also called herring fog because of their shape. In larger telescopes bright structures can be seen.
NGC 4656/57 is a galaxy 35 million light years away, which is in interaction with NGC 4631. It is rather faint and can be seen only in medium telescopes.
NGC 5195 is the smaller companion galaxy of M51. Both galaxies are connected by a bridge of matter. Due to the gravitational effect of the large galaxy NGC 5195 has been irregularly deformed. In a telescope, this galaxy appears as an appendage of the M51.
Some of the above galaxies belonging to the Local Group galaxies neighboring groups Canes Venatici I, Canes Venatici group and II group, both of which are named after this constellation.