Genitive: Canum Venaticorum
English: The Hunting Dogs
Size Ranking: 38th
Area: 465 square degrees
Fully Visible: 90°N-37°S
Canes Venatici was introduced in 1687 by the Polish astronomer, Johannes Hevelius. It consists of a sprinkling of faint stars, situated above Ursa Major, and represents two dogs, Asterion (‘little star’) and Chara (‘joy’), held on a leash by neighbouring Bootes, The Herdsman, as they pursue the Great Bear around the pole. Canes Venatici contains numerous galaxies, the most famous being M51, the Whirlpool, a beautiful face-on spiral. It was the first galaxy in which spiral form was detected, by Lord Rosse in 1845 using his 72 inch reflector at Birr Castle, Ireland.
Features of Interest:
αCVn, is popularly called Cor Caroli, meaning ‘Charles’s heart’, a reference to the executed King Charles I of England. This star is reputed to have shone particularly brightly in 1660 on the arrival of Charles II in England at the restoration of the monarchy. It consists of two white components, although delicate colour tints have been reported, magnitudes 2.9 and 5.6, separation 19.4”, PA 22.9°. The brighter component is an example of a rare class of stars with strong and variable magnetic fields; its brightness fluctuates slightly but not enough to be noticeable to the eye. The pair are 110ly away.
βCVn, named Chara, meaning ‘joy’, at magnitude 4.2, is the only other star of any prominence in this constellation. It is a yellow main sequence star, similar to the Sun, 27ly distant.
YCVn, 710ly away, is a semi-regular variable supergiant of deep red colour sometimes known as La Superba. Its range of magnitude is from about 5.0 to 6.5 with a period of approximately 160 days.
M3 (NGC 5272), is a rich globular cluster, located midway between Cor Caroli and Arcturus, αBoo, and is regarded as one of the finest globulars in the northern sky. At 6th magnitude it is on the naked eye limit, but can be seen as a hazy star in binoculars or a small telescope. Larger telescopes will resolve individual stars in its outer regions, while the main body of the cluster appears as a condensed ball of light with a faint outer halo. Telescope apertures of 100mm or more are needed to resolve individual stars in the outer regions. It is 32,00ly away.
M51 (NGC 5194), the Whirlpool galaxy, is an 8th magnitude spiral galaxy about 20 million ly away, with a smaller satellite galaxy, NGC 5195, apparently lying at the end of one its arms; in reality, this companion lies slightly behind M51, having brushed past it some time in the last 100 million years or so! The Whirlpool appears elongated showing a faint milky radiance around the star-like nuclei . Telescope apertures of at least 250mm are required to effectively see the arms.
M63 (NGC 5055), is a 9th magnitude spiral galaxy, visible as an elliptical haze with a mottled texture, and is popularly known as the Sunflower Galaxy because of its appearance in large telescopes.
M94 (NGC 4736), is a compact spiral galaxy presented nearly face-on. It looks like an 8th magnitude comet, with a fuzzy star-like nucleus surrounded by an elliptical halo. It is approximately 15 million ly away.
1. Redshift 2 – Maris Multimedia
2. The Guiness Book of Astronomy – Patrick Moore
3. Stars and Planets – Ian Ridpath and Wil Tirion
4. Where the Stars Are – Orion.
5. Sky Charts – Cartes du Ciel V 2.75