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Founded January 1970
Julian date: 2457724.16
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THE DAILY ASTRONOMER
Thursday, December 1,, 2016
The Pointer Queen
Polaris is not the brightest star. In fact, it ranks 48th in the list of the sky's brightest stars, right after Alphard (in Hydra) and just before Hamal (in Aries). As it is one of the few well known stars, Polaris is logically believe to also be the brightest. It isn't. Were it not for its current position close to the North Celestial Pole, we might pay it scant notice. However, Polaris is the sky's stellar cynosure and thus all stars appear to revolve around it. It occupies a prominent position in both the sky and our collective consciousness.
Polaris is also not directly overhead in our sky. Only a north pole observer would see it around the zenith. (As Polaris is not precisely aligned with the North Celestial Pole, it won't be precisely at the zenith at the North Pole. However. it would appear so close one couldn't tell the difference.) The observer's latitude determines the angle Polaris subtends relative to the northern horizon. An observer at 43 degrees north latitude would find Polaris 43 degrees north of the northern horizon. An observer at 10 degrees north latitude would find it 10 degrees north of the northern horizon. No observer south of the equator could find Polaris.
Well, if Polaris is not the brightest star and if it is not directly overhead, how should one be expected to find it? The answer to this question depends on the time of year. Now, in late autumn/early winter, one can use Cassiopeia the Queen as a guide. Like the Big Dipper, Cassiopeia is circumpolar, meaning that it will never set, at least not at this latitude. Also -like the Big Dipper- Cassiopeia describes a wide circle around Polaris every day. Its position also shifts slightly each day as a consequence of Earth's revolutionary motion around the Sun. Presently, Cassiopeia begins the evening near the zenith, while the Big Dipper rests low on the northern horizon. Six months from now -the first day in June when the Sun soars high in azure skies and no sorrow is possible- the Big Dipper begins the night at its top perch and the queen cowers close to the horizon.
Cassiopeia's lofty position makes it an idea guide right now. Just look straight up after dusk darkens into night an you'll observe the beautiful queen reclining at the apex. Follow its stars toward Polaris, which always remains in the same place.
The two guides. The circumpolar constellations Cassiopeia and Ursa Major can guide observers to find Polaris, the North Star. Ursa Major's most prominent feature is the "Big Dipper," an asterism consisting of its seven brightest stars. In the late autumn/early winter, Cassiopeia starts the night high in the sky and can therefore easily guide an observer to Polaris. In the spring/summer, the Big Dipper is high in the early evening and can serve as your "guide to Polaris."
One can determine the cardinal points by first finding Polaris. If one is facing Polaris, one is looking north. South is to the back. East is to the right and west to the left. We know that our part of the galaxy is teeming with objects and over populated with ancient constellations. Trying to find one's way in that celestial jungle is not for the faint hearted. However, by locating Polaris, one can get one's bearings and the exploration will be all that less difficult.