To the reader:

The Skywatcher's Diary for March 2006 has been prepared by Robert C. Victor, formerly Staff Astronomer (now retired). 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 http://www.pa.msu.edu/abrams/SkyCalendar/Index.html

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 be accessed at http://www.pa.msu.edu/abrams/SkyWatchersDiary/Diary.html

Current and back-issues of the Skywatcher's Diary are available in our archives at http://www.pa.msu.edu/abrams/SkyWatchersDiary/Archives.html
ftp://www.pa.msu.edu/pub/swd/

Naked-eye planets, Moon, and Stars in March

At dusk find Saturn in E to ESE halfway to overhead as March opens, ascending very high into SSE by month's end. Mars starts very high in SW at dusk, and ends month still high in WSW. For the first few days of March, fading Mercury might still be spotted very low in W in mid-twilight. Later in the evening, bright Jupiter rises in ESE about 5-1/2 hours after sunset on March 1, shifting earlier to within three hours after sunset at month's end. After Jupiter has risen, all three bright outer planets will be visible, spanning 162 degrees on March 1, 145 degrees on March 31.

Get outdoors by an hour before sunup, and you'll be rewarded by views of the two brightest planets, Venus in SE to ESE, and Jupiter in SSW to SW. You can see Venus in the daytime, just by keeping track of it until sunrise. A telescope then reveals that planet changing from a crescent about one-third full on March 1, to just over half full at month's end, and shrinking in apparent size as it recedes from Earth. Emerging Mercury can be spotted in morning mid-twilight the last week of March, just above horizon about 10 degrees south of east. Look for it to lower left of Venus, by 25 degrees on March 25, and 20 degrees on April 1.

The Moon was New on February 27, reaches First Quarter phase on March 6, Full on Mar. 14, Last Quarter on Mar. 22, and New on Mar. 29. The Moon appears near naked-eye planets on the following dates: As a thin young crescent to upper left of Mercury at dusk on March 1; as a fat crescent to lower right of Mars on evening of Mar. 5; in waxing gibbous phase near Saturn on evening of Mar. 10; in waning gibbous phase near Jupiter late in the evening on Mar. 18 until dawn on Mar. 19; as a waning crescent near Venus at dawn on Mar. 25 and 26; and as a very thin old crescent near Mercury at dawn on Mar. 27.

Stars: Around nightfall throughout March, look in the northeast for the well-known Big Dipper. Imagine its bowl to have a leaky bottom. Then the watery contents would pour onto the back of Leo the Lion, represented on our map by a Sickle (whose blade represents the mane of the Lion) and a triangle (representing the Lion's hindquarters). The star Regulus, at the handle of the Sickle, represents Leo's heart.

Extend a line connecting the Big Dipper's Pointer stars (the two stars in the front of the bowl) to point out Polaris, the North Star, always in the north. You can also use the Dipper to locate a much brighter but less well known star, Arcturus, by following the curve of the handle: "Follow the arc to Arcturus," which is shown on our map low in the east-northeast. To the right of Arcturus and below Leo is the constellation Virgo, half risen at the time of our map. In another hour, Virgo's brightest star, Spica, will have risen and be easy to see low in the east-southeast. Find that star by extending the curve of the Big Dipper's handle past Arcturus, and you'll "Drive a spike to Spica."

Leo and Virgo are constellations of the zodiac, the backdrop against which the Sun, Moon and planets are seen. In March we see these two constellations when we face away from the Sun, and so the Moon will be in their part of the sky for a few days around Full, which occurs on March 14.

Leo is facing west, toward two bright planets and a lineup of zodiac constellations. In order westward from Leo, they are: Cancer, the Crab, containing bright Saturn and the Beehive cluster of faint stars visible in the same binocular field; Gemini, containing the bright "Twin" stars, Pollux and Castor; Taurus, containing Mars and the similarly bright star Aldebaran marking the eye of the Bull, and two beautiful star clusters, the Hyades and the Pleiades; and Aries the Ram, about to set in the west-northwest. For most of March and into April, the Sun appears against the background of Pisces, the Fishes, below the map's western horizon.

The plane of the solar system or centerline of the zodiac in our March evening sky is pretty well defined by the line connecting Mars and Saturn extended toward both horizons. You'll notice that the line passes quite close to Regulus, and to Spica once that star has risen. The Twin stars Pollux and Castor are a little north of the line, while Aldebaran is a bit south. Orion and the two bright Dog Stars Sirius and Procyon which follow him across the sky are well south of the plane, while the Mother Goat star Capella and the Bear-chaser star Arcturus lie well to the north.

Following is a day-by-day guide to celestial happenings during March 2006. For drawings of many of these events, and an evening sky map, request a free sample copy of the Abrams Planetarium Sky Calendar by sending a self-addressed, stamped envelope to Sample Sky Calendar, Abrams Planetarium, Michigan State University, East Lansing, MI 48823. Or you can subscribe for $11 per year. We appreciate your subscriptions!

Skywatcher's Diary: March 2006