Sniff out the Hunting Dogs (Canes Venatici), the home of the magnificent Whirlpool Galaxy (M51) in the far northern sky, and you’ll find more galaxies than you can shake a stick at. Prominent Messier 106 (NGC 4258) is a superb spiral galaxy that holds its own in the company of the likes of the Sunflower Galaxy (M63) and M94. It’s bright enough to be found through a pair of binoculars and it looks like a galaxy through even a small telescope.
Where to look
Messier 106 is located in the north-western corner of Canes Venatici; sweep with a pair of 10 x 50 binoculars 1.7° south of the star 3 Canum Venaticorum (magnitude +5.2) and on a fine night you should spot a faint smudge of light. M106 is circumpolar (never setting) from UK shores, culminating late-month almost at the zenith at about midnight GMT.
An 80mm telescope (three-inch) can show its elongated disc, orientated south-east to north-west, while upgrading to a 150mm (six-inch) reveals a slightly mottled, oval-shaped core extending to perhaps 10’ x 7’, with a well-defined nucleus surrounded by a faint outer halo of nebulosity.
A big galaxy
Messier 106 is a large galaxy comparable in size with the Andromeda Galaxy (M31), and has somewhat of a resemblance to it. Its physical diameter of 135,000 light years at its neighbouring distance of 24 million light years give it a large apparent diameter on the sky of 18’ x 7.9’. M106 is a strong source of radio waves from its an active core, giving it a Seyfert II classification.
Amateurs now routinely capture superb images of M106 and widefield data can show a number of much smaller galaxies, including NGC 4217, an attractive edge-on spiral with a notable dust line that’s visible through a 200mm (eight-inch) telescope, and, closer in to M106, NGC 4248, a smaller still irregular that can be picked up through a 300mm (12-inch) ‘scope.
