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The Night Sky of March

Dr. Wayne Wooten
Professor of Astronomy

For March 2021, the moon is waning gibbous in the morning sky as the month begins, reaching last quarter on March 6th. The waning crescent in the predawn is just west of Saturn on March 9th, then south of Jupiter on March 10. It is new on March 13th, and Sunday March 14th sees the return of Daylight Savings Time. The waxing crescent passes south of Mars on March 19th. The Vernal Equinox begins spring on March 20th at 4:37 AM CDT. The first quarter moon is on March 21st. The full moon, the Paschal Moon, is on March 28th, so the following Sunday is Easter, April 4th for this year.

Mercury and Jupiter have a close conjunction in the dawn on March 3rd, but the innermost planet is too close to the Sun by midmonth. Venus too lies too close as well, reaching superior conjunction behind the Sun on March 26th, and will return to the evening sky by the end of April. Mars is the only evening sky planet, well up in the west in Taurus. It passes seven degrees north of similarly orange and bright Aldeberan in the eye of the Bull on March 20th. Brighter Jupiter and fainter Saturn are in the dawn, with Saturn 12 degrees west of Jupiter at month’s end.

The constellation Cassiopeia makes a striking W in the NW. South of Cassiopeia 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. 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 in the northwest. 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; it is directly above us as darkness falls in early March. 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 southern sky at dusk. The reddish supergiant Betelguese marks his eastern shoulder, while blue-white supergiant Rigel stands opposite on his west knee. How bright does Betelguese appear to you tonight? In 2019-20, this famed supergiant had expanded and cooled, forming a dust envelope that has darkened much of its southern hemisphere it to less than a quarter its normal brightness in visible light. As of February 2021, the dust has dissipated, and it is back close to its normal brightness as the alpha star of Orion again.

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 and among the youngest known stars.

In the east are 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 as darkness falls. 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, look for the bowl of the Big Dipper rising, with the top two stars, the pointers, giving you a line to find Polaris, the Pole Star. Here it sits unmoving 30 degrees high in on our northern sky locally. If you take the pointers of the Big Dipper’s bowl to the 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". The folk wisdom that "March comes in like a Lion" probably refers to the head of Leo rising just after sunset in early March below it).

Our highlight for March lies in the faint constellation Cancer, midway between the Gemini to the west and Regulus east of it. Almost directly overhead when darkness falls at month’s end, look under dark skies for a faint blur of light in the middle of the four stars that make up the crab’s body. This is the Praespe, or Beehive, cluster, M-44, familiar to the ancients. Its blurry appearance lead Charles Messier to include it in his catalog of things that look at first like comets, but do not move and are far away among the stars and galaxies. Now check it out with binoculars, and resolve it into dozens of stars, hence the "Beehive" title. This historic shot by Merry Edenton Wooten shows the Beehvie cluster to the right, resolved into slightly trailed stars in the 30" exposure, with blurry greenish Comet Iras-Arika-Alcock passing to the left of the constallation’s quadrilateral. At this time, this comet was making the closest approach of a comet to our planet in the 20th century, only three million miles away, and so close its motion could be tracked minute by minute with binoculars! The comet was also then passing directly behind earth on the ecliptic, our orbital path around the Sun. Had this several mile wide ball of ice reached that point only 2 days earlier, it would have collided with the earth, perhaps destroying civilization! Close call.

If you follow the handle of the Big Dipper to the south, by 9 PM you will be able to "arc to Arcturus", the brightest star of Spring and distinctly orange in color. Its color is an indication of its uniqueness. Its large speed and direction through the Milky Way suggests it was not formed with our Galaxy, but is a recent capture from the Sagittarius Dwarf Galaxy, a smaller satellite galaxy now being assimilated by our huge spiral galaxy. Many of its lost stars, like Arcturus, follow a band across the sky at about a 70 degree angle to our galactic plane. Arcturus is at the tail of kite shaped Bootes, the celestial bear driver chasing the two bears from his flocks. Spike south then to Spica in Virgo. Here appearance to the Greeks marked the time to plant, for they associated Virgo with Persephone, daughter of Ceres of the Harvest, returning from six months underground with Pluto to now bless the growth and greening of the upperworld. So when Spica rises now at sunset in the SE, it is time to plant your peas! Likewise, when Persephone goes back down to Hades and disappears in the sun’s glare in September SW skies, it is time to get your corn in the crib! This cycle of planting and harvesting by this star goes back to the dawn of civilization.

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