To the reader:
The Skywatcher's Diary for March 2001 has been prepared by
David Batch. Credit to the author and to
Abrams Planetarium,
Department of Physics and Astronomy at
Michigan State University, and mention of
our
Sky Calendar, would be
appreciated.
A sample issue of the Sky Calendar is available over the Internet. It
can be viewed via the World-Wide Web at
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If you would like a printed sample of the March issue, please send a long,
self-addressed stamped envelope to:
March Sky Calendar
Abrams Planetarium
Michigan State University
East Lansing, MI 48824
Each month, the Department of Physics and Astronomy at Michigan State
University makes the Skywatcher's Diary available over the Internet. It can
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http://www.pa.msu.edu/abrams/SkyWatchersDiary/Diary.html
Current and back-issues of the Skywatcher's Diary are available in our
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Skywatcher's Diary: March 2001
The Moon lies nearly between the two bright giant planets this evening - 3 degrees (6 moon diameters) to the left of Saturn and 7 degrees below Jupiter. By the time the Moon sets, around 1 a.m. tomorrow morning, it will have slid to within 4 degrees of Jupiter.
At 9:03 p.m. EST the Moon is at First Quarter. It forms a curved line with Jupiter and Saturn. Both planets are to the lower right. The bright star Aldebaran, eye of Taurus, is 3 degrees (6 moon diameters) below Luna.
The phase "comes in like a lion, goes out like a lamb" is often associated with the weather patterns of March. The imagery for the saying may originate with the stars. The constellation Aries, the Ram, is now setting in the WNW 4 hours after sunset, while Leo, the Lion, climbs the SE sky.
Venus continues to blaze in the western evening sky, now remaining up 3 hours after the sun. Use binoculars around sunset to glimpse the planet's slender crescent shape. You may need to mount the binoculars to a photo tripod in order to hold them steady enough. Sharp-eyed observers under near-perfect conditions might pick out the crescent without optical aid later in the month.
The bright evening planets - Venus, Saturn, Jupiter - are contained within an angle of 47 degrees - the minimum spread during the current evening appearance. As the weeks march on, all three planets drift toward the western horizon. Venus scampers faster than the giant planets, so the gap widens before Venus disappears.
In the south at dawn, Mars stands 5 degrees (half a fist) above Antares, the heart of Scorpius. The star and planet have been associated with one another since ancient times - primarily due to their similar color. Can you detect the reddish tint? Which object appears brighter? You will have no trouble distinguishing them as the month progresses and Mars brightens.
This evening the fat gibbous Moon stands 6 degrees (half a fist) above Regulus, the heart of Leo. At first light tomorrow morning, the Moon sits low in the west, 2 degrees (4 moon diameters) to the upper right of that star.
Tonight the Moon is between the two bright stars of Leo, the Lion. First-magnitude Regulus is 12 degrees (a fist width) to the upper right, and 2nd-magnitude Denebola, the lion's tail, is 14 degrees to the lower left. A line connecting the two stars passes 2 degrees above the Moon.
The Moon is Full at 23 minutes past noon EST today. Known to colonial Americans and Algonquin Indians as the Sap Moon, the March Full Moon heralded the coming of spring. This evening it rises just after sunset, slightly north of due east. As the sky darkens, look for Denebola, the lion's tail, 8 degrees (almost a fist width) to the Moon's upper left.
The Moon rises due east tonight, an hour and 20 minutes after sunset. By dawn tomorrow the Moon stands in the WSW. Spica, the brightest star in Virgo, then sits 11 degrees ( a fist) to the Moon's lower left.
Mercury stretches farthest west of the sun today - 27 degrees. Astronomers refer to this arrangement as "greatest elongation." Such configurations often create optimum conditions to observe the illusive planet - but not always. This time Mercury is challenging for northern skywatchers. Look low in the ESE 45 minutes before sunrise. Use binoculars. Much fainter Uranus is only 0.1 degree to the lower right of Mercury.
With the Moon not rising until early morning, the next two weeks are an ideal time to look for the zodiacal light. The ghostly pyramid shape sits on the western horizon at the end of twilight - about 1 1/2 hours after sunset. It is similar in brightness to the Milky Way, but broader at the base and more uniform. The phenomenon is caused by dust particles in the plane of the solar system scattering sunlight. Requires a very dark sky.
At the beginning of the month Venus set 3 hours after the sun. Now it follows Sol by only 2 hours. At month's end Venus drops out of sight. Be sure to note the planet's position every clear night, and try to detect its crescent phase with binoculars. Watch for changes in shape and size.
The Moon aids in spotting Mars the next two mornings. At dawn tomorrow, Luna is 5 degrees (half a fist) to the right of the Red Planet. The following morning the Moon has "hopped over" Mars and sits 7 degrees to its left.
At mid evening, the Milky Way rises out of the south, flows halfway up in the west, and descends to the north. On the southern horizon, amid the haze of the Milky Way, lies the minor constellation Vela, the Sails. It marks the "rear window" where we gaze backward to see where we've been, in our journey around the Galaxy.
The Moon reaches Last Quarter at 3:45 p.m. EST this afternoon. Tomorrow morning the fat crescent hangs over the "teapot" pattern of stars that highlights Sagittarius. This constellation also lies in the direction of our galaxy's center. The precise point is 9 degrees (a fist width) to the lower right of the Moon.
Although St. Patrick's Day has no direct astronomical connection, it has acquired a strong seasonal association, particularly in Ireland. Traditionally, the date marked the beginning of the growing season, when the soil awakened. Peas, the earliest vegetable, were sowed, and the cows were put out to pasture.
Some dark evening look for the Praesepe, or Beehive, star cluster. It sits between the brighter Gemini twin, Pollux, and Regulus, in Leo. To the unaided eye the cluster has the appearance of a faint patch of light. Binoculars reveal numerous stars. As you gaze at the group, your eyes absorb 600-year-old starlight. In other words, the Praesepe is located 600 light years from Earth.
Venus sets 1 1/2 hours after sunset. The timing is changing dramatically. A week from now the lag is only 40 minutes, as Venus drops abruptly. Around sunset, observe the planet's crescent phase in binoculars or telescope as it grows larger and thinner.
The Vernal Equinox occurs at 8:31 a.m. this morning, as the sun crosses into the northern celestial hemisphere. At that moment the sun passes directly overhead at a spot on the Earth's equator in the eastern Atlantic ocean off the African coast, SW of Liberia.
The Moon and Mercury present a challenge for experienced observers tomorrow morning. Look for the thin crescent just above the ESE horizon 30 minutes before sunrise. Mercury is 5 degrees (10 moon diameters) to the Moon's left. Use binoculars.
Jupiter and Saturn are noticeably farther apart than earlier this month. The orbits of the two planets carry them both eastward among the stars of Taurus. Jupiter's orbit, being closer to the sun, shuttles Jove faster, and it gradually pulls away from its ringed neighbor.
Mars is now nearer than one Astronomical Unit, or just under 93 million miles, from Earth. The distance will shrink to 0.45 A.U. by June 13, when Mars passes closer to us than it has since 1988. Prepare for a grand show.
New Moon occurs at 8:21 p.m. EST. Tomorrow evening you have the unusual opportunity to see a crescent Moon less than 24 hours old (past new). Look just above the western horizon 20 minutes after sunset. Venus is 14 degrees (1 1/2 fists) to the Moon's right. Take your binoculars.
Over the next several days skilled observers have the rare chance to spot Venus both before sunrise and after sunset on the same day! Venus appears within 10 degrees to the upper left of the sun at sunrise and to the upper right at sunset. Look approximately 20 minutes before sunrise and after sunset. Use binoculars.
The photogenic two-day-old Moon beckons in western twilight. Look for the "old moon in the young moon's arms" - the shadowy upper portion cupped in the bright crescent. Venus is 22 degrees (two fists) to the lower right, but look early - the planet sets 40 minutes after sundown.
An hour after sunset the Moon sits halfway between the horizon and Saturn. It is passing through a faint part of the zodiac that contains no bright stars or easily recognized star patterns. Can you determine the direction of the sun below the horizon? Imagine the crescent is a bow. It shoots an arrow straight at the sun.
This evening the Moon hangs 3 degrees (6 moon diameters) below Saturn. Tomorrow night it poses 3 degrees beside Jupiter, creating an eye-catching sight. Aldebaran, the orange eye of Taurus, is just to the Moon's left. The Moon and surrounding area provide ample targets for binocular and telescopic exploration.
The brilliant star Arcturus - the brightest in the springtime constellation of Bootes, the Herdsman - rises in the ENE at sunset. Look for it as the sky darkens. Verify that you have the right star by following the curve of the Big Dipper's handle to Arcturus.
Venus is in conjunction with the sun today. Most people visualize this to mean that the planet is directly in line with the sun. Because Venus' orbit is tilted relative to the Earth's, direct alignment rarely occurs. This time Venus passes 8 degrees north of the sun. It is this relatively wide gap between the two bodies that allowed us the rare opportunity to spot Venus both before sunrise and after sunset on a single day.
You may recall Mars was directly above Antares, the scorpion's heart, early this month. Find it before dawn in the south and confirm that it now lies 11 degrees (one fist) to the left (east) of Antares. The planet continues its eastward journey until early May when it reverses direction for two months, traveling westward, back toward Antares.