NGC 253 The Silver Dollar Galaxy
The Silver Dollar Galaxy is a good target for observation with a telescope with a 300 mm diameter or larger. In such telescopes, it appears as a galaxy with a long, oval bulge and a mottled disk. Although the bulge appears only slightly brighter than the rest of the galaxy, it is fairly extended compared to the disk. In 400 mm scopes and larger, a dark dust lane northwest of the nucleus is visible, and over a dozen faint stars can be seen superimposed on the bulge. This beautiful galaxy was discovered by Caroline Herschel in 1783 during one of her systematic comet searches. About half a century later, John Herschel observed it using his 18 inch metallic mirror reflector at the Cape of Good Hope. He wrote, "very bright and large (24′ in length); a superb object.... Its light is somewhat streaky, but I see no stars in it except 4 large and one very small one, and these seem not to belong to it, there being many near..." In 1961 Allan Sandage wrote in the Hubble Atlas of Galaxies that the Sculptor Galaxy is "the prototype example of a special subgroup of Sc systems....photographic images of galaxies of the group are dominated by the dust pattern. Dust lanes and patches of great complexity are scattered throughout the surface. Spiral arms are often difficult to trace.... The arms are defined as much by the dust as by the spiral pattern." B. Y. Mills, working out of Sydney, discovered that the Sculptor Galaxy is also a fairly strong radio source.