Canes Venatici is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for ‘hunting dogs,’ and the constellation is often depicted in illustrations as representing the dogs of Boötes, the Herdsman, a neighboring constellation. The constellation is bordered by Ursa Major to the north and west, Coma Berenices to the south, and Boötes to the east. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 12h 06.2m and 14h 07.3m, while the declination coordinates are between +27.84° and +52.36°. Covering 465 square degrees, it ranks 38th of the 88 constellations in size.
The stars of Canes Venatici are not bright. In classical times, they were included by Ptolemy within the constellation Ursa Major in his star catalogue.
In medieval times, the identification of these stars with the dogs of Boötes arose through a mistranslation. Some of Boötes’s stars were traditionally described as representing the club of Boötes. When Ptolemy’s Almagest was translated from Greek to Arabic, the translator Hunayn ibn Ishaq did not know the Greek word and rendered it as the nearest-looking Arabic word, writing ‘al-`aşā dhāt al-kullāb,’ which means ‘the spearshaft having a hook.’ When the Arabic text was later translated into Latin, the translator Gerard of Cremona mistook the Arabic word ‘kullāb’ for ‘kilāb,’ meaning ‘dogs,’ writing ‘hastile habens canes’ (‘spearshaft having dogs’). In 1533, the German astronomer Peter Apian depicted Boötes as having two dogs with him.
These spurious dogs floated about the astronomical literature until Hevelius decided to specify their presence in the sky by making them a separate constellation in 1687. Hevelius chose the name Asterion (from the Greek ‘αστέριον,’ meaning ‘little star’) for the northern dog, and Chara (from the Greek ‘χαρά,’ meaning ‘joy’) for the southern dog, as Canes Venatici, the Hunting Dogs, in his star atlas. In his star catalogue, the Czech astronomer Bečvář assigned Asterion to β CVn (Canes Venatici) and Chara to α CVn.
Constellations of Canes Venatici and Boötes
[http://www.davidmalin.com/fujii/source/CVn.html]
[http://astropixels.com/constellations/charts/CVn.html]
Cor Caroli seen from northern England on March 1, 2011
Cor Caroli (Alpha Canum Venaticorum) is the brightest star in Canes Venatici. The name Cor Caroli means ‘Charles’ Heart,’ and was named in the 17th century to honour the King Charles I of England who was beheaded in 1649.
Great Diamond
[https://en.wikipedia.org/wiki/Great_Diamond]
Cor Caroli marks the northern vertex of the Diamond of Virgo asterism. It is a binary star consisting of two distantly separated components with a combined apparent magnitude of 2.81. The two stars are 19.6 arcseconds apart in the sky and are easily resolved in small telescopes. The system lies approximately 110 light years from Earth. The brighter of the two stars is designated α² Canum Venaticorum, the fainter α¹ Canum Venaticorum.
α² Canum Venaticorum has spectral type A0, and has an apparent visual magnitude which varies between 2.84 and 2.98, with a period of 5.47 days. It is a chemically peculiar star with a strong magnetic field, about 5,000 times as strong as the Earth’s, and is also classified as an Ap/Bp star. Its atmosphere has overabundances of some elements, such as silicon, mercury, and europium. This is thought to be due to some elements sinking down into the star under the force of gravity while others are elevated by radiation pressure. This star is the prototype of a class of variable stars, the so-called α² Canum Venaticorum stars. The strong magnetic field of these stars is believed to produce starspots of enormous extent. Due to these starspots the brightness of α² Canum Venaticorum stars varies considerably during their rotation.
α¹ Canum Venaticorum is a F-type main sequence star. It is considerably fainter than its companion and has an apparent visual magnitude of approximately 5.60.
[https://en.wikipedia.org/wiki/Cor_Caroli]
Beta Canum Venaticorum has the name Chara which means Joy in Greek. It 27.53 light-years (8.44 parsecs) distant from the Earth. At apparent magnitude 4.26, Beta Canum Venaticorum is the second brightest star in the constellation. It has a stellar classification of G0 V, and so is a G-type main sequence star.
Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. The spectrum of this star shows a very weak emission line of singly ionized calcium (Ca II) from the chromosphere, making it a useful reference star for a reference spectrum to compare with other stars in a similar spectral category. (The Ca-II emission lines are readily accessible and can be used to measure the level of activity in a star’s chromosphere.)
Beta Canum Venaticorum is considered to be slightly metal-poor, which means it has a somewhat lower portion of elements heavier than helium when compared to the Sun. In terms of mass, age and evolutionary status, however, this star is very similar to the Sun. As a result, it has been called a solar analog. It is about 3% more massive than the Sun, with a radius 12% larger than the Sun'’s and 15% greater luminosity.
[https://en.wikipedia.org/wiki/Beta_Canum_Venaticorum]
La Superba
Y Canum Venaticorum (Y CVn) is a very rare star in planet Earth’s night sky. It’s also very red, exhibiting such a remarkable spectrum of light, 19th century astronomer Angelo Secchi dubbed it La Superba. Located 710 light-years away in northern constellation Canes Venatici (the Hunting Dogs), the star varies in brightness over a period of about half a year. Near maximum, it becomes just bright enough to see with the unaided eye, but the star’s beautiful red hue is easy to see in binoculars or a small telescope. In fact, La Superba is among the brightest of the carbon stars- cool, highly evolved red giant stars with exceptional abundances of carbon. The carbon is created by helium fusion near the stellar core and dredged up into the stars’ outer layers. The resulting overabundance of simple carbon molecules (like CO, CN, C2) in the atmospheres of carbon stars strongly absorbs bands of bluer light and gives these stars a deep red color. La Superba is losing its carbon-rich atmosphere into the surrounding interstellar material through a strong stellar wind, and could be near the beginning of a transition to a planetary nebula phase.
[http://apod.nasa.gov/apod/ap081218.html]
M51: The Whirlpool Galaxy
Follow the handle of the Big Dipper away from the dipper’s bowl until you get to the handle’s last bright star. Then, just slide your telescope a little south and west and you might find this stunning pair of interacting galaxies, the 51st entry in Charles Messier famous catalog. Perhaps the original spiral nebula, the large galaxy with well defined spiral structure is also cataloged as NGC 5194. Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (right), NGC 5195. The pair are about 31 million light-years distant and officially lie within the angular boundaries of the small constellation Canes Venatici. Though M51 looks faint and fuzzy to the eye, deep images like this one can reveal striking colors and the faint tidal debris around the smaller galaxy.
[http://apod.nasa.gov/apod/ap150502.html]
Messier 63: The Sunflower Galaxy
A bright spiral galaxy of the northern sky, Messier 63 is about 25 million light-years distant in the loyal constellation Canes Venatici. Also cataloged as NGC 5055, the majestic island universe is nearly 100,000 light-years across. That’s about the size of our own Milky Way Galaxy. Known by the popular moniker, The Sunflower Galaxy, M63 sports a bright yellowish core in this sharp, colorful galaxy portrait. Its sweeping blue spiral arms are streaked with cosmic dust lanes and dotted with pink star forming regions. A dominant member of a known galaxy group, M63 has faint, extended features that could be the result of gravitational interactions with nearby galaxies. In fact, M63 shines across the electromagnetic spectrum and is thought to have undergone bursts of intense star formation.
[http://apod.nasa.gov/apod/ap140313.html]
Starburst Galaxy M94
What could cause the center of M94 to be so bright? Spiral galaxy M94 has a ring of newly formed stars surrounding its nucleus, giving it not only an unusual appearance but also a strong interior glow. A leading progenitor hypothesis holds that an elongated knot of stars known as a bar rotates in M94 and has generated a burst of star formation in the inner ring. Recent observations have revealed the outer, fainter ring is not closed and relatively complex. M94, pictured here spans about 30,000 light years, lies about 15 million light years away, and can be seen with a small telescope toward the constellation of the Hunting Dogs (Canes Venatici).
[http://apod.nasa.gov/apod/ap150526.html]
The Whale and The Hockey Stick
NGC 4631 is a big beautiful spiral galaxy seen edge-on (top right) only 25 million light-years away towards the small northern constellation Canes Venatici. This galaxy’s slightly distorted wedge shape suggests to some a cosmic herring and to others the popular moniker of The Whale Galaxy. Either way, it is similar in size to our own Milky Way. In this gorgeous color image, the Whale’s dark interstellar dust clouds, yellowish core, and young blue star clusters are easy to spot. A companion galaxy, the small elliptical NGC 4627, appears above the Whale Galaxy. At the lower left is another distorted galaxy, the hockey stick-shaped NGC 4656. The distortions and mingling trails of gas detected at other wavelengths suggest that all three galaxies have had close encounters with each other in their past. The Whale Galaxy is also known to have spouted a halo of hot gas glowing in x-rays.
[http://apod.nasa.gov/apod/ap071012.html]
Mount Lemmon SkyCenter image of Messier 3
Messier 3 (also known as M3 or NGC 5272) is a globular cluster of stars in Canes Venatici. It was discovered by Charles Messier on May 3, 1764, and resolved into stars by William Herschel around 1784. Since then, it has become one of the best-studied globular clusters. Identification of the cluster’s unusually large variable star population was begun in 1913 by American astronomer Solon Irving Bailey and new variable members continue to be identified up through 2004.
Many amateur astronomers consider it one of the finest northern globular clusters, following only Messier 13. M3 has an apparent magnitude of 6.2, making it a difficult naked eye target even with dark conditions. With a moderate-sized telescope, the cluster is fully defined. It can be a challenge to locate through the technique of star hopping, but can be found by looking almost exactly halfway along an imaginary line connecting the bright star Arcturus to Cor Caroli. Using a telescope with a 25 cm (9.8 in) aperture, the cluster has a bright core with a diameter of about 6 arcminutes and spans a total of 12 arcminutes.
This cluster is one of the largest and brightest, and is made up of around 500,000 stars. It is estimated to be 8 billion years old. It is located at a distance of about 33,900 light-years away from Earth.
Messier 3 is located 31.6 kly (9.7 kpc) above the Galactic plane and roughly 38.8 kly (11.9 kpc) from the center of the Milky Way. It contains 274 known variable stars; by far the highest number found in any globular cluster. These include 133 RR Lyrae variables. Messier 3 is considered ‘metal-rich;’ that is, for a globular cluster, it has a relatively high abundance of heavier elements.
[https://en.wikipedia.org/wiki/Messier_3]
The most barren place in the observable Universe: The Canes Venatici Supervoid (A.K.A. the Giant Void).
The Canes Venatici Supervoid (also known simply as the Giant Void) is an immensely vast region of space with an extreme under-density of galaxies. It is the largest confirmed void to date, with an estimated diameter of 1 to 1.3 billion light years, and is approximately 1.5 billion light years away. It was discovered in 1988, and continues to be the largest void ever detected. Even the hypothetical ‘Eridanus Supervoid’ is utterly dwarfed by this void. The void’s location in the sky is close to the Boötes void. To compare, the Boötes void is 5 times nearer to us, but is one-fourth of the size of the Giant Void.
[http://imgur.com/gallery/IwutU7o]
[https://en.wikipedia.org/wiki/Canes_Venatici]
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