My first Magazine Sky & Telescope - 04.2019

APRIL 2019 OBSERVING Deep-Sky Wonders M101 NGC 5195 NGC 5195 W N NGC 5194 NGC 5194 NW W N NGC 5907 p Left: Together, NGC 5194 and NGC 5195 form M51. The spiral galaxy NGC 5194 was discov- ered in 1773 by Charles Messier; Pierre Méchain discovered the smaller NGC 5195 in 1781. In 1845, William Parsons, 3rd Earl of Rosse, revealed M51’s spiral structure with his 71-inch refl ecting telescope. Right: Look for bright cores at the center of NGC 5194 and NGC 5195. The sketch here shows a view of the pair at 164×. Seek out more aperture and magnifi cation to study NGC 5194’s elegant arms. streams enwrap the galaxy, like a still shot of a pirouetting dancer twirling long, gossamer scarves around her svelte form. There are two schools of thought on the origin of these cosmic streams. Some research suggests that they arise from a low-mass, orbiting companion progressively torn asunder and drawn thin by the tidal forces of NGC 5907. Other ﬁndings indicate they may be the fossil signatures of an ancient merger of two comparatively large galaxies, the smaller one at least one-eighth the mass of the other. On star-ﬁlled, transparent nights, invest some time exploring these wonderful galaxies to see what features you can elicit from their milky glow. The more you familiarize yourself with them, the more these distant friends will reveal to you. ¢ Contributing Editor SUE FRENCH loves the challenge of hunting down de- tails in complex galaxies no matter what scope she’s using. W N p Top: This sketch shows the center of M101 at 164×. This galaxy can be diffi cult to pick up due to its low surface brightness, but once lo- cated, it takes magnifi cation well. M101’s arms spark with star-forming regions. Steady skies and patience will help you trace these stellar knots. Bottom: NGC 5907 is a sharp slice of light in Draco. From Earth, we’re looking at the spiral galaxy edge-on. Though there’s no ap- parent central bulge, look for a brightening to- ward the galaxy’s center. The author sketched this view at 102×. Object Type Dist. (Ml-y) Mag(v) Size/Sep RA Dec. Messier 81 Spiral 12 6.9 26.9′ × 14.1′ 9 h 55.6 m +69° 04′ Messier 82 Non-Magellanic irregular 13 8.4 11.2′ × 4.3′ 9 h 55.9 m +69° 41′ Messier 65 Weakly barred spiral 31 9.3 9.8′ × 2.9′ 11 h 18.9 m +13° 06′ Messier 66 Weakly barred spiral 31 8.9 9.1′ × 4.2′ 11 h 20.2 m +13° 00′ NGC 3628 Peculiar spiral 31 9.5 14.8′ × 3.0′ 11 h 20.3 m +13° 35′ NGC 5194 Peculiar spiral 24 8.4 11.2′ × 6.9′ 13 h 29.9 m +47° 12′ NGC 5195 Non-Magellanic irregular 24 9.6 5.8′ × 4.6′ 13 h 30.0 m +47° 16′ Weakly barred spiral 22 7.9 28.8′ × 26.9′ 14 h 03.2 m +54° 21′ Spiral 47 10.3 12.8′ × 1.4′ 15 h 15.9 m +56° 20′ Messier 101 NGC 5907 Angular sizes and separations are from recent catalogs. Visually, an object’s size is often smaller than the cataloged value and varies according to the aperture and magnifi cation of the viewing instrument. Right ascension and declination are for equinox 2000.0. 56 A PR I L 2 019 • SK Y & TELESCOPE Small-Scope Galaxies

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