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The Night Sky of February

Dr. Wayne Wooten
Professor of Astronomy

For February 2013, the Moon will be last quarter on February 3rd; it sits 3.5 degrees south of Saturn, with both rising about midnight. The moon is new on February 10th. If you have clear skies and a flat SW horizon, look for a nice grouping of Mars, Mercury, and the waxing crescent moon about 45 minutes after sunset on February 11th; binoculars may be needed to see this nice twilight grouping. The first quarter moon is high overhead at dusk on February 17th, and passes just south of Jupiter the following evening. The full moon is on February 25th; this is the “hunger” moon in Native American tradition, when most of the food store up for winter was almost gone. The first two weeks find the moon waning in the morning sky, then waxing in the evening sky for the middle weeks of this month. The moon is waning, rising just after sunset for the last three days of the month.

Mercury and Mars are briefly visible just after sunset in the SW, with a nice grouping with the crescent moon on February 11th. Mars is lost in the sun’s glare soon after, and Mercury also vanishes into the sun’s glare by February 24th. Venus lies behind the sun now, not to appear in evening skies until April. Jupiter dominates the night sky, high up in the NE at sunset in Taurus. It has retrograded west past Aldeberan, the bright orange eye of the Bull. Check out the four Galilean moons in a scope, and the belts and zones and Great Red Spot on the disk of the largest planet with it high in the sky in the evening sky. Saturn is now in Libra, and rising about 11 PM by month’s end. The ringed planet will be coming to opposition on April 28th. The rings are gradually starting to open up again, but still rather thin, only tilted about 1 degrees now, compared to 27 degree when fully opened at Saturn’s solstice in 2016; when this open, the huge reflecting surface of the ring’s ice boulders will double the planet’s brightness.

The constellation Cassiopeia makes a striking W in the NW. She contains many nice star clusters for binocular users in her outer arm of our Milky Way, extending to the NE now. Her daughter, Andromeda, starts with the NE corner star of Pegasus’’ Square, and goes NE with two more bright stars in a row. It is from the middle star, beta Andromeda, that we proceed about a quarter the way to the top star in the W of Cassiopeia, and look for a faint blur with the naked eye. M-31, the Andromeda Galaxy, is the most distant object visible with the naked eye, lying about 2.5 million light years distant. Overhead is Andromeda’s hero, Perseus, rises. Between him and Cassiopeia is the fine Double Cluster, faintly visible with the naked eye and two fine binocular objects in the same field. Perseus contains the famed eclipsing binary star Algol, where the Arabs imagined the eye of the gorgon Medusa would lie. It fades to a third its normal brightness for six out of every 70 hours, as a larger but cooler orange giant covers about 80% of the smaller but hotter and thus brighter companion as seen from Earth.

At Perseus’ feet for the famed Pleiades cluster; they lie about 400 light years distant, and over 250 stars are members of this fine group. East of the seven sisters is the V of stars marking the face of Taurus the Bull, with bright orange Aldebaran as his eye. The V of stars is the Hyades cluster, older than the blue Pleaides, but about half their distance. The southern horn of Taurus marks one of the most historic places in the sky. Here in 1054 AD, a supernova bright enough to be seen in broad daylight appeared for several weeks. The star that blew up created the Crab Nebula, Messier 1. The French comet hunter Charles Messier noted it looked like a comet, a blur in the sky, but unlike comets, was not moving night by night in orbit about the sun. This started him on a historic listing of 110 objects comet hunters should avoid, now the list of the best deep sky objects in the sky. The shattered star has a rapidly spinning neutron star (the fainter of the two stars in its center) that pulses 30 times a second. Our photo is by EAAA astrophotographer Ed Magowan; note the red color of the glowing hydrogen, the lightest and most rapidly expanding gas in this example of cosmic recycling. It is in red giant stars like Aldeberan and Betelguese that the heavier elements like carbon and iron are forged, and in supernovae such as this that they are blown back into space. Most of the atoms of our bodies were made in such a star perhaps five billion years ago, and our solar system was made of its ashes; we are all, as Carl Sagan says, “star dust”.

Yellow Capella, a giant star the same temperature and color as our much smaller Sun, dominates the overhead sky. It is part of the pentagon on stars making up Auriga, the Charioteer (think Ben Hur). Several nice binocular Messier open clusters are found in the winter milky way here. East of Auriga, the twins, Castor and Pollux highlight the Gemini. UWF alumni can associate the pair with Jason and the Golden Fleece legend, for they were the first two Argonauts to sign up on his crew of adventurers.

South of Gemini, Orion is the most familiar winter constellation, dominating the eastern sky at dusk. The reddish supergiant Betelguese marks his eastern shoulder, while blue-white supergiant Rigel stands opposite on his west knee. Just south of the belt, hanging like a sword downward, is M-42, the Great Nebula of Orion, an outstanding binocular and telescopic stellar nursery. The bright diamond of four stars that light it up are the trapezium cluster, one of the finest sights in a telescope.

In the east rise the hunter’s two faithful companions, Canis major and minor. Procyon is the bright star in the little dog, and rises minutes before Sirius, the brightest star in the sky. Sirius dominates the SE sky by 7 PM, and as it rises, the turbulent winter air causes it to sparkle with shafts of spectral fire. Beautiful as the twinkling appears to the naked eye, for astronomers this means the image is blurry; only in space can we truly see “clearly now”. At 8 light years distance, Sirius is the closest star we can easily see with the naked eye from West Florida.
When Sirius is highest, along our southern horizon look for the second brightest star, Canopus, getting just above the horizon and sparkling like an exquisite diamond as the turbulent winter air twists and turns this shaft of starlight, after a trip of about 200 years!

To the northeast, a reminder of Spring coming; look for the bowl of the Big Dipper to rise, with the top two stars, the pointers, giving you a line to find Polaris, the Pole Star. But if you take the pointers south, you are guided instead to the head of Leo the Lion rising in the east, looking much like the profile of the famed Sphinx. The bright star at the Lion’s heart is Regulus, the “regal star”. Fitting for our cosmic king of beasts, whose rising at the end of this month means March indeed will be coming in like a Lion.

March could bring the best comet since Hale-Bopp in 1997 to northern hemisphere skies. Comet PANSTARRS will pass the sun heading north about March 10th, and may be an easy naked eye object with a fine tail for the rest of March in the evening sky. It is hoped that Comet ISON in November and December will be even brighter, but it will be best seen by us in the morning skies. More of these promising comets in months to come.

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