Three Clusters in Auriga
A multitude of open clusters adorns the Auriga region of the Milky Way. The prettiest is M37, but nearby M36 and M38 have their own charm. Click on the image to see the entire constellation of Auriga.
Courtesy Akira Fujii.
Galactic clusters are legion in the winter Milky Way, and overhead Capella shepherds a profusion of them in Auriga. The prettiest of these is M37,
dimly visible to the naked eye on extremely clear nights, a little southeast of the midpoint of a line from Beta (β) Tauri to Theta (θ) Aurigae. In binoculars or small finders, M37 appears as a milky patch, while a 3-inch shows a fine swarm of stars. In his 5.9-inch refractor, W. H. Smyth saw "the whole field being strewed as it were with sparkling gold-dust." M37 is also the most striking of the three Messier clusters in the constellation, the brightest (visual magnitude 6.2), and has the most stars 150, according to the Atlas Catalogue.
The cluster is rather open, that is, the stars are not impressively concentrated toward the center. Whether your telescope is a small instrument or a large reflector, M37 is a treat. The view is further enhanced by the background of the Milky Way.
Nearby is M36, a rich cluster of fainter stars, somewhat smaller than M37, but also impressive. The cluster measures 12' in diameter and contains 60 stars. It's sparse compared to M37, and visually the stars tend to form a blunt cross.
Moving "down" the Milky Way we run into such variegated star fields and clusters that it's almost impossible to know where to halt, but this might very well be at M38. Although this cluster is well within the star-strewn Milky Way, it's usually visible to the naked eye without much effort. Evenly compressed into a glowing ball two-thirds the diameter of the full Moon are over 100 softly blazing stars. M38 is magnificent in any sized instrument. Photographs usually show a departure from circularity, a feature quite evident to visual observers. (For more on open clusters visible during the winter, see "Winter Clusters Galore.")