Map 7: North Equatorial 4
Ursa Major to Hercules
August 6, 2007
This map, like the last, is chock-full of bright galaxies. They mainly reside in the 38th-largest constellation, Canes Venatici, and in Coma Berenices, number 42 on the constellation-size list. In contrast, the 13th-largest constellation, Boötes, has far fewer deep-sky objects.
Start by observing two globular clusters. Magnitude 9 NGC 5466 in Boötes appears uniform in brightness. A 12-inch scope reveals two dozen bright stars set against a background glow of unresolvable faint stars.
The other globular is M3 in Canes Venatici's southern reaches. It lies midway between Cor Caroli (Alpha Canum Venaticorum) and Arcturus (Alpha Boötis). Even small telescopes reveal a lot of detail in this magnitude 5.9 cluster, but point a 12-inch its way, and you'll find a grainy sphere with a bright center and more than 100 stars near its edge.
Also in Canes Venatici, you'll find such standout galaxies as the Sunflower Galaxy (M63) and the fabulous Whirlpool Galaxy (M51). Point any scope at these objects under a dark sky, and you won't be disappointed. But lesser-known star cities also inhabit this constellation.
Almost 3° north of Beta Canum Venaticorum lies the irregular galaxy NGC 4449. This galaxy has quite a different appearance: rectangular. It measures 4' by 2' and shines at magnitude 9.6.
Look 2° southwest of 5th-magnitude 6 Canum Venaticorum for NGC 4244. This magnitude 10.4 edge-on spiral galaxy shows disparity between its length and width — it measures 15' by 2'.
Find NGC 5005 3° southeast of Alpha Canum Venaticorum. This magnitude 9.8 spiral is an oval twice as long as wide. Most telescopes allow you to pick out an extended central region with a bright nucleus. A nice foreground star shines at 9th magnitude 12' west of NGC 5005.
Coma Berenices contains eight Messier objects, seven of which are galaxies. The exception is globular cluster M53, which lies 1° northeast of Alpha Comae Berenices. You can resolve the outer stars of this magnitude 7.5 object, but its central region, although broad, is too concentrated.
The galaxies Messier cataloged (M64, M85, M88, M91, M98, M99, and M100) are all spirals and worth detailed observing sessions. A fun way to compare these objects is to make small sketches of them on the same sheet of paper. An example of an elliptical galaxy is NGC 4494, which lies 3° south-southeast of Gamma Comae Berenices. This magnitude 9.8 galaxy measures 2' across and is ever-so-slightly oval.
Cap off your night viewing objects in Coma with NGC 4565, a spectacular magnitude 9.6 edge-on spiral with a small central bulge. Large scopes will reveal a dust lane; it runs the whole length of the galaxy but is easiest to see silhouetted against the core.
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