Canes Venatici as depicted inHevelius's star atlas. Note that, per the conventions of the time, the image is mirrored.Canes Venatici can be seen in the orientation it appears to the eyes in this 1825 star chart fromUrania's Mirror.
The stars of Canes Venatici are not bright. In classical times, they were listed byPtolemy as unfigured stars below the constellationUrsa Major in hisstar catalogue.
Inmedieval 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 theclub (Greek:κολλοροβος,kollorobos) of Boötes. When the Greek astronomer Ptolemy'sAlmagest was translated from Greek toArabic, the translatorHunayn ibn Ishaq did not know the Greek word and rendered it as a similar-sounding compound Arabic word for a kind of weapon, writingالعصا ذات الكُلابal-'aşā dhāt al-kullāb, which means 'the staff having a hook'.
When the Arabic text was later translated into Latin, the translator,Gerard of Cremona, mistookكُلابkullāb ('hook') forكِلابkilāb ('dogs'). Both written words look the same in Arabic text withoutdiacritics, leading Gerard to write it asHastile habens canes ('spearshaft-having dogs').[3]In 1533, the German astronomerPeter Apian depicted Boötes as having two dogs with him.[4]
These spurious dogs floated about the astronomical literature until Hevelius decided to make them a separate constellation in 1687.[5] Hevelius chose the nameAsterion[a] for the northern dog andChara[b] for the southern dog, asCanes Venatici, 'the hunting dogs', in hisstar atlas.[7]
In his star catalogue, the Czech astronomerAntonín Bečvář assigned the namesAsterion to β CVn andChara to α CVn.[8]
Canes Venatici is bordered byUrsa Major to the north and west,Coma Berenices to the south, andBoötes to the east. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "CVn".[10] The official constellation boundaries, as set by Belgian astronomerEugène Delporte in 1930,[9] are defined by a polygon of 14 sides.
In theequatorial coordinate system, theright ascension coordinates of these borders lie between12h 06.2m and14h 07.3m, while thedeclination coordinates are between +27.84° and +52.36°.[2] Covering 465 square degrees, it ranks 38th of the 88 constellations in size.
Canes Venatici contains no very bright stars. TheBayer designation stars,Alpha andBeta Canum Venaticorum are only of third and fourthmagnitude respectively.Flamsteedcatalogued 25 stars in the constellation, labelling them 1 to 25 Canum Venaticorum (CVn); however, 1CVn turned out to be in Ursa Major, 13CVn was in Coma Berenices, and 22CVn did not exist.[11]
Alpha Canum Venaticorum, also known asCor Caroli ('heart of Charles'), is the constellation's brightest star, named by SirCharles Scarborough in memory ofKing Charles I, the executed king of Britain.[12][c] The English astronomerWilliam Henry Smyth wrote in 1844 that α CVn was brighter than usual during theRestoration, asCharles II returned to England to take the throne, but gave no source for this statement, which seems to be apocryphal.[14] Cor Caroli is a widedouble star, with a primary of magnitude 2.9 and a secondary of magnitude 5.6; the primary is 110 light-years from Earth. The primary also has an unusually strong variable magnetic field.[12]
Beta Canum Venaticorum, or Chara, is a yellow-huedmain sequence star of magnitude 4.25,[15] 27 light-years from Earth. Its common name comes from the word for joy.[12] It has been listed as an astrobiologically interesting star because of its proximity and similarity to the Sun.[16][17] However, no exoplanets have been discovered around it so far.[15]
AM Canum Venaticorum, a very blue star of magnitude 14, is the prototype of a special class ofcataclysmic variable stars, in which the companion star is awhite dwarf, rather than a main sequence star. It is 143 parsecs distant from the Sun.[19]
TheGiant Void, an extremely largevoid (part of the universe containing very few galaxies), is within the vicinity of this constellation. It is regarded to be thesecond largest void ever discovered, slightly larger than theEridanus Supervoid and smaller than the proposedKBC Void and 1,200 times the volume of expected typical voids. It was discovered in 1988 in a deep-sky survey. Its centre is approximately 1.5 billion light-years away.[22]
Canes Venatici contains fiveMessier objects, including fourgalaxies. One of the more significant galaxies in Canes Venatici is theWhirlpool Galaxy (M51, NGC 5194) andNGC 5195, a small barredspiral galaxy that is seen face-on. This was the first galaxy recognised as having a spiral structure, this structure being first observed byLord Rosse in 1845.[12] It is a face-on spiral galaxy 37 million light-years from Earth. Widely considered to be one of the most beautiful galaxies visible,M51 has manystar-forming regions andnebulae in its arms, coloring them pink and blue in contrast to the older yellow core. M 51 has a smaller companion, NGC 5195, that has very few star-forming regions and thus appears yellow. It is passing behind M 51 and may be the cause of the larger galaxy's prodigious star formation.[23]
NGC 4707 is a spiral galaxy roughly 22 million light-years from Earth.[26]
Other notable spiral galaxies in Canes Venatici are theSunflower Galaxy (M63, NGC 5055),M94 (NGC 4736), andM106 (NGC 4258).
M63, the Sunflower Galaxy, was named for its appearance in large amateur telescopes. It is a spiral galaxy with an integrated magnitude of 9.0.
M94 (NGC 4736) is a small face-on spiral galaxy with approximate magnitude 8.0, about 15 million light-years from Earth.[12]
NGC 4631 is a barred spiral galaxy, which is one of the largest and brightest edge-on galaxies in the sky.[27]
M3 (NGC 5272) is aglobular cluster 32,000 light-years from Earth. It is 18′ in diameter, and at magnitude 6.3 is bright enough to be seen withbinoculars. It can even be seen with the naked eye under particularly dark skies.[12]
M94, also cataloged as NGC 4736, is a face-on spiral galaxy 15 million light-years from Earth. It has very tight spiral arms and a bright core. The outskirts of the galaxy are incredibly luminous in theultraviolet because of a ring of new stars surrounding the core 7,000 light-years in diameter. Though astronomers are not sure what has caused this ring of new stars, some hypothesize that it is from shock waves caused by abar that is thus far invisible.[23]
^Hevelius' name for the northern dog, Asterion, is from the Greekαστέριον, meaning the 'little star',[6] thediminutive ofαστηρ 'the star' or 'starry'. (Allen 1963, p. 115)
^Hevelius' name for the southern dog, Chara, means 'joy' in Greek, but 'dear' or 'beloved' in Latin.(Allen 1963, p. 115)
^According to Warner,[13] it was originally namedCor Caroli Regis Martyris ('The Heart of King Charles the Martyr') forCharles I. Warner also notes that suggestions that the name was invented by Edmond Halley are erroneous.
^Kunitzsch, P.; Smart, T. (2006).A Dictionary of Modern Star Names: A short guide to 254 star names and their derivations (2nd revised ed.). Sky Publishing. p. 22.ISBN1-931559-44-9.
^Wagman, Morton (October 2003).Lost Stars: Lost, missing and troublesome stars from the catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and sundry others. Blacksburg, VA: McDonald and Woodward. p. 366.ISBN978-0-939923-78-6.
Kunitzsch, P. (1959).Arabische Sternnamen in Europa (in German). Otto Harassowitz.Bibcode:1959ase..book.....K.
Ptolemäus, Claudius (1974).Der Almagest: Die Syntaxis Mathematica des Claudius Ptolemäus in arabisch-lateinischer Ūberlieferung. Translated by Kunitzsch, P. Otto Harassowitz.
Ridpath, Ian; Tirion, Wil (2017),Guide to Stars and Planets (5th ed.), Princeton University Press,ISBN9780691177885
Kunitzsch, P. (1990).Der Sternkatalog des Almagest die arabisch-mittelalterliche Tradition (in German). Vol. II Die lateinische Ūbersetzung Gerhards von Cremona. Otto Harassowitz.
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![NGC 4248 is located about 24 million light-years away.[24]](/mt/?noimg=&dark=on&url=http%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aA_cosmic_atlas_NGC_4248.jpg)
![NGC 4242 is a dim galaxy in Canes Venatici.[25]](/mt/?noimg=&dark=on&url=http%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aDim_and_diffuse.jpg)
![NGC 4707 is a spiral galaxy roughly 22 million light-years from Earth.[26]](/image.pl?url=http%3a%2f%2fen.wikipedia.org%2f%2fupload.wikimedia.org%2fwikipedia%2fcommons%2fthumb%2f6%2f6a%2fNGC_4707_-_HST_-_Potw1651a.tif%2flossy-page1-120px-NGC_4707_-_HST_-_Potw1651a.tif.jpg&f=jpg&w=240)
