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The Night Sky of February

Dr. Wayne Wooten
Professor of Astronomy

For February, the New Moon February 1st. The slender waxing crescent is four degrees south of Jupiter in twilight on February 2nd, and by month’s end, all the naked eye planets will behind the Sun or in the dawn sky. First quarter moon is February 8th, and the Full Moon, the Hunger or Wolf Moon, is February 16th. Last quarter is February 23rd. The waning crescent rejoins the dawn planets at month’s end, passing below brilliant Venus and below it, much fainter and redder Mars, on February 27th.

Having swiftly passed between us and the Sun in late January, Mercury is low in the SE dawn sky in mid February, reaching greatest western elongation, 26 degrees in front of the Sun, on February 16th, just below and to the left of bright Venus and Mars. It disappears into Sun’s glare by month’s end. But Venus will dominate the dawn during most of 2022. It is at its brightest as a brilliant crescent on February 7th, and continues to pull away from the Sun and wax in phase until summer. Mars is south of Venus, moving slowly eastward. It will come to opposition this fall. Both Jupiter and Saturn are lost in the Sun until March.

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.

Cassiopeia’s 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, about 2.5 million light years away.

Overhead is Andromeda’s hero, Perseus. 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; use it (mag. +0.9) as a comparison star to measure the fading of Betelguese. The V of stars is the Hyades cluster, older than the blue Pleiades, but about half their distance.

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; they were the first two recruits for the Argonauts of the University of West Florida.

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. Betelguese is also known as alpha Orionis, for it has been the brightest star in Orion most of the time. But for much for 2019 it faded due to an expulsion of condensing carbon dust (soot) blown off in our direction, and was only 1/3rd its greatest brightness. But now this cloud has dissipated and it is back close to normal.

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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. Just east of Betelguese is the fine binocular cluster NGC 2244. But the much fainter Rosette Nebula that it lies in the center of requires bigger scopes or astrophotography.

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 before Sirius, the brightest star in the sky. Midway between them is the fine Rosette Nebula, a star nursery including the nice open cluster NGC 2244, easily found in binoculars. Appropriate for Valentine’s Day, here is our cosmic rose, with much gas and the same kind of dark dust Betelguese blew out, but now not marking a star’s death, but birth of new solar systems like our own, with the dust becoming us, residents of terrestrial rocky worlds like Earth.

The beautiful Rosette Nebula, aka NGC 2237, lies about 5,200 light-years from Earth in the constellation Monoceros the Unicorn, and is about 130 light-years across. It is an emission nebula, meaning that the gases that compose it glow as they are energized by radiation from local stars. The young stars in the nebula’s center are gravitationally bound to each other; they are an open cluster formed together from the material of the nebula.

Sirius dominates the SE sky by 7 p.m., 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. For a sense of stellar distances, consider sunlight is eight minutes old by the time it warms your face. So the light from Sirius has taken the number of minutes in a year (eight minutes versus eight years), or 60 x 24 x 365.25 = 525,960 times; Sirius is more than a half million times distant than our Sun. While it is 21x more luminous than our Sun in reality, no wonder the Sun rules the day! And Sirius is the closest star you can easily see from here. Almost every thing you see in the night sky must be millions of times more distant from us than our home star.

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 that spring is 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".

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