Canes Venatici is one of those constellations that beginners often overlook — but usually regret ignoring. It's easy to find (sandwiched between the handle of the Big Dipper and the brilliant orange star Arcturus), modest in appearance, and yet home to some truly spectacular objects that reward anyone with binoculars or a telescope.
The Mythology
Canes Venatici translates as "the Hunting Dogs." In various European traditions — French, German, and others — the name and concept remain consistent: a pair of dogs held on a leash. One charming interpretation pictures the dogs chasing the Big Bear (Ursa Major, of which the Big Dipper is the most recognizable part).
Old French star maps depicted Canes Venatici as the end of a long celestial river coursing past the Big and Little Bears, then Leo and Cancer, before terminating at the northern constellation Camelopardalis. It's a shame that so many of the whimsical, creative objects on those old maps didn't carry over into the modern system.
Cor Caroli — A Colorful Double Star
The brightest star in Canes Venatici, Cor Caroli, was named by English astronomer Edmond Halley (of comet fame) to honor King Charles II. Through a telescope it reveals itself as a beautiful double star — and a classic example of how subjective star color perception can be.
Experienced observers have described the colors of Cor Caroli's pair as "flushed white & pale lilac," "pale yellow and fawn," "white and pale olive blue," and "white and pale copper" — all describing the same pair of stars. See our article on star colors for more on why this happens.
M51 — The Whirlpool Galaxy
In the northern part of Canes Venatici lies one of the most famous galaxies visible to amateur astronomers: M51, the Whirlpool Galaxy. Discovered by Charles Messier in 1773 and later recognized as a spiral galaxy by Lord Rosse, M51 is a showpiece because we view it nearly face-on — allowing us to see the structure of its spiral arms directly.
Through a small telescope under dark skies, M51 appears as a fuzzy oval with a brighter core, possibly showing a hint of the companion galaxy NGC 5195 at its edge. A larger aperture begins to reveal the spiral arm structure. From a truly dark site, M51 can even be glimpsed in binoculars as a faint smudge about 35 million light-years away.
M3 — One of the Sky's Finest Globular Clusters
At the other end of Canes Venatici lies M3, one of the most spectacular globular clusters in the northern sky. This ancient ball of roughly 500,000 stars sits about 34,000 light-years away and shines with the combined light of approximately 160,000 Suns.
The nearby bright orange star Arcturus (in neighboring Boötes) makes finding M3 easier — it lies roughly halfway between Arcturus and Cor Caroli. In binoculars, M3 appears as a bright, non-stellar smudge. A telescope at moderate power begins to resolve its outer edges into individual stars; higher power reveals a dazzling sphere of stars concentrated toward a blazing core.