My first Magazine Sky & Telescope - 01.2019

Under the Stars by Fred Schaaf The Many Directions of Winter January offers ample opportunities for many celestial scenes. H ow can you go out on a clear dark January evening and not look at Orion and his surrounding host of bril- liant constellations? Sirius, the Pleia- des, Orion’s Belt, Betelgeuse and Rigel, Aldebaran and the Hyades, Pollux and Castor, the gleam in Orion’s sword that is the Orion Nebula . . . all are sights that immediately vie for your rapt atten- tion. This mere eighth or so of the cur- rently visible sky is like a cymbal crash of stellar splendor on a January evening. But shouldn’t we also listen to more subtle strains of “music” from other parts of the orchestra of the January evening sky? Let’s mostly consider the state of the sky at just one time on January evenings: the time when the sky looks as it does on the all-sky map at the center of the magazine. The Perseus-pinnacled sky. The Pleiades are just short of the meridian on our map, but the constellation ﬁ gure whose extended foot points to the clus- ter is right at the zenith for viewers near latitude 40° north. I’m referring to one of the brightest of all constellations, one that’s also the most important in the biggest and arguably richest myth in all the heavens. This constellation, of course, is Perseus, “the hero” or “the champion.” At the time of our sky map, Perseus is overhead and surrounded by all the other neighboring constellations that represent ﬁ gures in his myth: Androm- eda (his wife-to-be); Cassiopeia and Cepheus (eventually his mother-in-law and father-in-law); Pegasus (the winged Comet Tago-Sato-Kosaka horse he released from captivity); and Cetus (ofﬁ cially the Whale but anciently known as a sea monster of unspeci- ﬁ ed type that Perseus slew to rescue Andromeda). And Beta (β) Persei, the renowned variable star Algol, marks the severed head of Medusa, held by Perseus as he ﬂ oats at the top of the sky. Perseus encompasses several naked- eye star clusters, the Little Dumbbell Nebula (M76), the huge, elusive Cali- fornia Nebula (NGC 1499), and more. And at the time of our map — 8 p.m. local time in early January and dusk in late January — Perseus is at the very pinnacle of the sky. Of course, not everyone wants to crane their neck or wrestle with their alt-azimuth mount at its most awk- ward position to study sights near the zenith. But at the very least it’s grand to be aware that while Orion ﬂ ames about halfway up the southeastern sky, Perseus’s nest of brightness and interest sparkles directly over our heads. Embers of summer in winter. If you don’t want to look straight up on a January evening, how about look- ing towards the remnants of summer? Even in January, Cygnus, the Swan, can be observed in the early evening with its Northern Cross asterism standing upright on the horizon just south of northwest. And at the time of our map, summer’s brilliant blue-white Vega is setting almost exactly in the northwest while winter’s brilliant blue-white Sirius is low almost in the due southeast. These two stars aren’t far from the exact forward viewpoint (Vega) and exact backward viewpoint (Sirius) out of our galaxy-orbiting solar system. Every ﬁ rst-magnitude star in one night? The sky visible on a Janu- ary evening at the time of our map is interesting enough. But if we gaze, at least off and on, through the entirety of a long January night we can survey several seasons’ worth of sights. Can you even observe every ﬁ rst-magnitude (and brighter) star visible from around 40° north in the course of one of these nights? At dawn, Antares is certainly visible (near Venus and Jupiter this month). But can you catch Altair at dusk or dawn? I know Fomalhaut is vis- ible at some January dusks because I saw my ﬁ rst comet, with both telescope and naked eye, below Fomalhaut in January 1970. That object was Comet Tago-Sato- Kosaka, the precursor of spring 1970’s much greater Comet Bennett. ¢ Contributing Editor FRED SCHAAF is the author of 13 books, including The Brightest Stars. sk yandtele scope.com • JA N UA RY 2 019 45

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