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The Night Sky of February

Dr. Wayne Wooten
Professor of Astronomy

For February 2024, the last quarter moon is on February 2nd. In the morning sky, the waning crescent passes 5 degrees south of Venus on February 7th, then 4 degrees south of Mars on February 8th. The new moon is on February 9th, only two months until the big total solar eclipse of April 8, 2024 runs though Middle America.

Back in the evening sky, the waxing crescent moon passes 2 degrees below Saturn in the SW twilight on February 10th. On the 15th, the almost first quarter moon passes e degrees north of Jupiter overhead. The full moon, the Hunger Moon, rises at sunset on February 24th.

Mercury is below Venus and Mars in the dawn on February 1st, but quickly disappears behind the Sun for the rest of the month. Venus too is heading behind the Sun, and passes Mars in the dawn on February 22nd. Mars moves farther away from the Sun in the dawn sky through out the month, but remain on the other side of the Sun. In interesting advantage of this current position is that the rover cameras on Mars’ surface can image sunspots on the far side of the Sun, pointed away from us, and give us a week’s advance notice that a good one is coming soon over the Sun’s eastern limb as seen from earth.

Jupiter rides high overhead in Aries in the sunset sky, and its moons are easy to spot with small telescopes. But Saturn is soon gone, low in the SW as the month begins, and lost in the sun’s glare by the end of the month.

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 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. Now this cloud has dissipated.

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 is the Rosette Nebula that lies around the cluster. The red of the petals is colored by ionized hydrogen, or an H II region. H I is just optically invisible neutral hydrogen, which can be mapped with radio telescope at 21 cm wavelength. II indicates the hydrogen atom is hot enough to ionize, with its single electron kicked up to higher energy orbitals. The particular red color is the emission line created by the electron falling from the third to the second excited state, and is the same red color I hope you witness on April 8th as the bright red prominences extending over the limb of the totally eclipsed sun! The energy to ionize this gas comes from the hot young B class stars, just born in the center. So these clusters are forming from the inside out, with the expanding gases also rolling up the dark tendrils of carbon dust you see well at the top of my shot. This is as Carl Sagan said so well, "us" stuff, the leavier carbon, nitrogen, oxygen, calcium, iron, sulfur, and phosphorus created in supernovae and making our planet and bodies.

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. 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. 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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