Canes Venatici is a small constellation, consisting of only two stars. However, it is quite easy to find due to its location just south of the Big Dipper. Like many of the surrounding constellations, Canes Venatici holds quite a few galaxies.
M51, the Whirlpool Galaxy, is one of the most well-known galaxies in the sky. Although it is within the boundaries of Canes Venatici, the easiest way to find M51 is by looking 3½° southwest of Alkaid, the star at the end of the Big Dipper’s handle. M51 is a face-on spiral galaxy with a smaller companion galaxy connected to it by an extension of one of the spiral arms.
Like all galaxies, M51 is much easier to find and observe under a dark sky with little light pollution. From a dark site, M51 is faintly visible with binoculars as a small fuzzy spot of light. The unique shape of the two interacting galaxies is easily visible with most telescopes, although the spiral structure is a bit harder to observe. By carefully observing M51 using averted vision, the spiral structure can be seen with mid-sized telescopes.
M106 is another relatively bright spiral galaxy in Canes Venatici. M106 is tilted at an angle toward Earth, giving it an oblong shape. To find M106, imagine a line connecting the star Chara in Canes Venatici with Phad, the star on the southeast corner of the Big Dipper’s bowl. M106 is near the midpoint of this line, just to the west of it. M106 is similar in brightness to M51, but its spiral arms are less obvious and are not visible in smaller telescopes.
Cor Caroli, the brighter of the two stars making up Canes Venatici, is a beautiful double star. The component stars are separated by about 20 arcseconds, making them easy to split with low magnification (50x or less). The primary star is white, while the secondary is slightly yellow.
NGC 4631 (the Whale Galaxy) and NGC 4656 (the Hockey Stick Galaxy) are a fascinating pair of galaxies in the southern part of Canes Venatici. The two galaxies lie about ½° apart, so they are visible in the same telescopic field of view at moderate magnifications. This galaxy pair is located about 6° southwest of Cor Caroli.
Both galaxies are oriented edge-on to Earth, but they look fairly different from each other. NGC 4631 is the larger and brighter of the two galaxies, and it really does bear some resemblance to a whale. This galaxy is quite mottled with light and dark areas.
NGC 4656 is smaller and fainter, but one of its ends is bent at nearly a 90° angle, giving the galaxy the appearance of a hockey stick. Low magnification works well for finding these galaxies and comparing them in the same field of view. Higher magnifications will help reveal the details in each galaxy.
Nearly all of the deep sky objects in Canes Venatici are galaxies, but the constellation holds one beautiful globular star cluster, M3. This cluster is located between Cor Caroli and Arcturus, the brightest star in the nearby constellation Bootes. M3 lies straight between the two stars and slightly closer to Arcturus. The cluster looks like a small fuzzy spot with binoculars. An 8” telescope should resolve the cluster fairly well.