To the reader:
The Skywatcher's Diary for March 1999 has been prepared by
Robert C. Victor. 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/
There are two Full Moons in March: See Diary enties for March 1, 31.
Four planets are in west at dusk in early March, but two soon depart.
Venus shines at mag. -4 in W at dusk. Venus sets in a dark sky, nearly 2-1/2 hours after sunset on Mar. 1, increasing to 3 hours after sunset at month's end. Jupiter (mag. -2) is below or lower right of Venus, starting 6 degrees from Venus on March 1, and 1 degree farther from it each day. Jupiter sinks into twilight glow around midmonth. Mercury stays 4 or 5 degrees lower right of Jupiter March 1-12, but fades rapidly and disappears in second week. Its brightness fades from magnitude -0.4 on Mar. 2, to +0.6 on Mar. 7, and +2.2 on Mar. 12. Saturn (mag. +0.5) is 20 degrees upper left of Venus March 1, 2.4 degrees south (left) of Venus on March 19, and 13 degrees below Venus on March 31. Young crescent Moon passes near planets in the west at dusk on March 18-20.
Late evening until dawn: Mars rises in ESE, within 5 hours after sunset on Mar. 1, and within 2.5 hours after sunset on Mar. 31. At dawn, Mars is in SSW to SW, and is the brightest morning "star." Mars brightens sharply this month, from mag. -0.2 on March 1 to mag. -1.1 on March 31, as the red planet's distance from Earth shrinks from 84 to 62 million miles. Mars is 17 to 19 degrees E of first-magnitude Spica this month and follows that star across the night sky. The Moon passes Mars and Spica on nights of March 4-6 and nights of April 1 and 2; see Diary.
Skywatcher's Diary: March 1999
The Moon is Full overnight, at 1:58 a.m. EST on Tuesday (10:58 p.m. PST tonight). This is the first of two Full Moons this month; the next will occur on the 31st at 5:49 p.m. EST. The second Full Moon within a calendar month has come to be called a "Blue Moon." For an article about the origin of this term, see the March issue of Sky & Telescope magazine, pp. 52-55, or visit
http://www.skypub.com/sights/moonplanets/mar99bluemoon.html
November 2001, 32 months from now, is the next time there'll be two Full Moons in a single month. The usual waiting time between Blue Moons is 30-35 months. But this year, after the Blue Moon of Jan. 31, we need wait only two months for the next, on March 31. Not until the year 2018 will a calendar year include two months having two Full Moons each. As in 1999, the months with two Full Moons will be January and March, because February is the only month short enough to sometimes have no Full Moon.
Tonight's Sap or Crow Moon (as it was called by Native and Colonial Americans) is on the opposite side of the sky from the Sun and is up all night, rising north of east just before sunset on Monday and setting north of west just after sunrise on Tuesday. From a place with unobstructed views, try to observe Sun and Moon simultaneously on both occasions.
As evening twilight deepens, look for a spectacular display of four planets low in the western sky. Not until April-May 2002 will a greater number of naked-eye planets (all five) be simultaneously visible. Venus is the brightest, with Jupiter, next in brilliance, 6 degrees to its lower right. Mercury is almost as far to Jupiter's lower right. Finally, Saturn is 20 degrees to Venus' upper left. In the east, the star Regulus, heart of Leo the Lion, is about 9 degrees to Moon's upper right.
The Moon, just past full, rises about 35 minutes after sunset, 8 degrees north of due east. In the west, Venus shines, with Jupiter 7 degrees lower right. The gap between these two bright planets widens by one degree per day, until Jupiter sinks into twilight in about two weeks. Mercury, now 5 degrees to Jupiter's lower right, reaches its highest position in the evening sky for this year tonight and Wednesday, but will fade quickly next week.
Look in the west before nightfall to see four naked-eye planets fit within 30 degrees! Mercury is the lowest and sets first, about as the Moon rises around nightfall; Saturn is highest and sets latest, nearly 4 hours after sunset.
From latitude of Boston and East Lansing MI westward across the
U.S., the Moon rises about 2-1/2 hours after sunset tonight, and about an hour later each night for next few nights. The sky is moonless at nightfall through Mar. 18, and at very dark sites the zodiacal light appears as a huge, nearly vertical cone of dim light in the west. How far from the Sun can you detect its glow? Venus, low in west at nightfall, is 30 degrees from the Sun, and Saturn is now 46 degrees from Sun.
From a fantastically dark site, you may be able to trace the zodiacal light
even past the Pleiades, now 76 degrees from Sun. For more on this phenomenon, see
http://www.earthsky.com/1996/es960308.html and
http://antwrp.gsfc.nasa.gov/apod/ap970826.html
Four hours after sunset on Thursday, March 4, look for Spica low in ESE, about 8 degrees lower left of the waning gibbous Moon. Golden Arcturus is just north of east, 27 degrees to Moon's left. You can also find these two bright stars by extending the curve of the Big Dipper's handle: "Follow the arc to Arcturus and drive a spike to Spica." In another hour, Mars will have risen in ESE, 23 degrees lower left of Moon and 18 degrees lower left of Spica. By an hour before sunrise on Friday, Moon is in SW, with Spica 6 degrees lower left, and Mars in SSW, some 20 degrees to Moon's left.
See all five bright planets, four simultaneously in early evening, and one much later in the night! Within an hour after sunset, find brilliant Venus low in west, with Jupiter 10 degrees lower right. Mercury is just 4 degrees lower right of Jupiter this evening, the closest they'll appear to each other during this apparition of Mercury. Saturn is 16 degrees upper left of Venus. Five hours after sunset, Mars has just risen in ESE, about 11 degrees to Moon's lower left. Spica is about 9 degrees to Moon's upper right, and Arcturus is in east, 27 degrees to Moon's upper left. For the rest of the night, Arcturus, Mars, and Spica form a huge isosceles triangle with Arcturus at the apex, 33 degrees from the other two objects. Mars-Spica are 18 degrees apart. The Moon is within the triangle. At some time overnight, the Moon is equidistant from Mars and Spica, 10 degrees from each, forming another isosceles triangle. When it occurs depends on your location: Soon after Mars rises and before 11 p.m. Friday from the West Coast, and around 3 a.m. Saturday from the East. On Saturday an hour before sunup, Moon is in SW, with Mars 9 degrees left and Spica 11 degrees lower right (from Michigan), and Arcturus 28 degrees upper right.
At nightfall in early March, the Milky Way passes just WSW of overhead. Follow its course from Cassiopeia in NW, upward through Perseus, then west and south of overhead through Auriga and past the horns of Taurus and feet of Gemini, then down through the Winter Triangle in the S and through the star clouds of Puppis southeast of Canis Major. The Milky Way of winter is more subtle and less bright than its summer counterpart, because as we look up toward the horns of Taurus, we are facing away from the bright center of our Galaxy. If you have trouble seeing many stars, the zodiacal light or the Milky Way despite clear skies, your problem may be light pollution. For newsletters, solutions, membership information and much more, see the webpage of the International Dark-Sky Association at: http://www.darksky.org
Five hours after sunset, Mars is very low in ESE, some 2 to 3 degrees to the right of the waning gibbous Moon. By an hour before sunup on Sunday, they're in SSW, with Mars about 4 degrees to Moon's lower right. Mars will double in brilliance by month's end.
Mornings next week are excellent for using binoculars to view lunar surface features, as the Moon passes Last Quarter phase (half full) on Wednesday.
All this week, Jupiter and Saturn are 25 degrees apart, with brilliant Venus about midway between them tonight and Monday. Mercury is just over 4 degrees to Jupiter's right tonight. Look from 45 minutes to an hour after sunset. Use binoculars to keep Mercury in view until the latest possible date as it fades rapidly this week.
Tonight and Tuesday at dusk, the lineup of four planets takes up its smallest span, 27 degrees. An hour before sunup on Tuesday, the waning gibbous Moon is in south, with reddish Antares, heart of Scorpius, twinkling 9 degrees below.
An hour before sunup on Wednesday, the Moon is a little east of due south and at Last Quarter phase, half full. Antares is nearly 14 degrees to Moon's lower right. Later, as you face the rising Sun, note the Moon is about 90 degrees or a quarter-circle to your right, and that the Moon's left half is illuminated. From Thursday through next Monday, follow the Moon's waning crescent as it moves closer to the Sun each morning.
At dusk, brilliant Venus is in west, with Saturn 10 degrees upper left, and Jupiter 15 degrees lower right. Use binoculars to see Mercury, still within 5 degrees right of Jupiter. By Friday, Mercury-Jupiter will be 5.4 degrees apart, the same separation as the Pointer Stars of the Big Dipper's bowl, the ones which point toward the North Star. Can you fit both those stars within the field of your binoculars simultaneously?
Three planets are still easy to see with unaided eye at dusk, in a straight line 25 degrees long: Saturn at the top end of the line, brilliant Venus 9 degrees lower, and Jupiter at the lower end, 16 degrees from Venus. Use binoculars to see Mercury, nearly faded to 2nd magnitude; look for it 5 degrees right of Jupiter and slightly lower.
Early this evening, Saturn is 8 degrees upper left of Venus, and Jupiter 17 degrees to Venus' lower right. Mercury, faded to mag. +2.2, is quite a challenge in bright twilight. Using binoculars, look 5.4 degrees lower right of Jupiter. In only a week, on March 19, Venus will pass within 2.4 degrees of Saturn; Mercury will pass inferior conjunction, nearly between Earth and Sun, and its dark side will face Earth.
The Cowboy Astronomer is presented Fridays and Saturdays at 8:00 p.m., and Sundays at 4 p.m., at Abrams Planetarium. Noted cowboy humorist Baxter Black narrates this homespun jaunt through the night sky. Our family show, Rusty Rocket's Last Blast, is presented Sundays at 2:30 p.m.
Two more mornings to see the waning crescent Moon: On Sunday, an hour before sunup, it's very low, about 30 degrees south of east. At the same time on Monday, it's just rising in ESE. The three brightest morning "stars" then, in order of brightness, are Mars in SW; Arcturus high in WSW; and Vega, very high in E.
Last easy chance to see the old crescent Moon: Forty-five minutes before sunup on Monday, the thin crescent has just risen in ESE. The southeastern U.S. gets their final chance on Tuesday, when Moon will be very low in E to ENE 30 minutes before sunup.
At dusk, Jupiter is nearly due west, 20 degrees lower right of Venus, and Saturn is just 5 degrees to Venus' upper right. To increase your chances of catching a glimpse of Jupiter, look early, about 30 minutes after sunset, and choose a place with a clear view of the western horizon. Binoculars will help. Later this week, watch Venus overtake Saturn, the Moon overtake both planets, and Jupiter sink into bright twilight. Look nightly!
The Moon will be New on Wednesday at 1:48 p.m. EST. Your first chance to glimpse the young Moon will be on Thursday at dusk. More on Thursday.
Back in January's morning sky, Mars passed just 4 degrees above Spica. Now Mars has moved 19 degrees east of Spica and begins to retrograde, or move west, toward that star. Four hours after sunset these evenings, Mars is rising in ESE, 19 degrees lower left of Spica. By one-and-a-half hours before sunrise, Mars is in SSW, while Spica is in SW, 19 degrees to Mars' lower right. Keep track of Mars and Spica in coming months as they move closer together and climb high into the evening sky. In late spring, reddish Mars and blue-white Spica will form a strikingly colorful "double star" less than 2 degrees apart.
Half an hour after sunset, look for the young Moon low in west. Jupiter is about 7 degrees to Moon's lower right, and Venus some 18 degrees above the Moon. As the sky darkens, Saturn is 2.6 degrees to Venus' left. Tomorrow, we'll give directions for using the Moon to locate Venus in the daytime, and a description of Friday evening's compact gathering of three solar system bodies.
Can you see Venus in the daytime? Four hours before sunset, Venus is high in the south, some 7 or 8 degrees to the upper left of a slender crescent Moon. By sunset, Venus is still 30 degrees up in WSW to W, 33 degrees to Sun's upper left and 6 degrees to Moon's upper right. Don't miss this evening's spectacle! As twilight deepens, look for Saturn just 2.4 degrees to Venus' lower left. The compact gathering of crescent Moon with earthshine, Saturn, and Venus may just fit within the field of 7-power binoculars. Keep track of the trio tonight until it sets, and watch for changes.
Spring begins today at 8:46 p.m. EST, as the Sun stands directly over Earth's equator. An hour after sunset this evening, the Venus-Saturn pair, still 2.6 degrees apart, lies about 12 degrees lower right of the waxing crescent Moon.
At nightfall in the western sky, the crescent Moon is accompanied by first magnitude Aldebaran, eye of Taurus, 11 degrees to Moon's upper left, and the Pleiades star cluster, 10 degrees to Moon's upper right. Far to Moon's lower right, Venus and Saturn are now 3.3 degrees apart. Within 4 degrees right and lower right of Aldebaran lie the 3rd and 4th- magnitude stars of the Hyades star cluster, forming the head of the Bull. Each of the items mentioned here is a worthy subject for observation with binoculars.
An hour after sunset, Aldebaran lies just 3 or 4 degrees to Moon's lower right, while Saturn lies 4 degrees to Venus' lower left. This week is excellent for viewing the Moon with binoculars and telescopes.
An hour after sunset, in the west, Venus is now 5 degrees above Saturn. The fat crescent Moon, approaching First Quarter phase, is high in SW, 11 degrees upper right of reddish Betelgeuse, shoulder of Orion. Some 19 degrees lower is blue-white Rigel, the Hunter's foot. About midway between these two bright stars lies Orion's three-star belt. Follow the belt left toward Sirius, the brightest star, in the south, and rightward toward Aldebaran, eye of Taurus, in the WSW.
The Moon, now just past First Quarter phase and slightly more than half full, lies high in SSW an hour after sunset. Look for Betelgeuse about 18 degrees to Moon's lower right, Procyon about the same distance to Moon's lower left, and Pollux and Castor, the Gemini twins, 16 degrees to Moon's upper left.
The waxing gibbous Moon is high in the south as nightfall approaches, while Venus is in the west, 7 degrees above Saturn. Look for Procyon in Canis Minor 13 degrees below the Moon, and Pollux in Gemini 9 degrees above. Castor is 4-1/2 degrees from Pollux. Procyon completes the nearly equilateral Winter Triangle with Sirius and Betelgeuse.
Tonight, Mars rises 6 minutes before Venus sets, so if you have unobstructed views toward ESE and WNW, it's theoretically possible to see both at once. Each successive evening, it gets easier to do so. By March 31, Mars rises 40 minutes before Venus sets. On what date can you first spot Mars before Venus sets?
The Moon is high in SE an hour after sunset, with Regulus, heart of Leo the Lion, within 8 degrees lower left.
An hour after sunset, Moon is in ESE, with Regulus 5 degrees upper right. Can you still find Saturn? Look low in W, 10 degrees below Venus.
An hour after sunset, the Moon is in ESE, with Regulus, heart of Leo, 18 degrees to its upper right, and 2nd-magnitude Denebola, tail of the Lion, 11 degrees to the Moon's left.
An hour after sunset, find Saturn low in the west, 12 degrees below brilliant Venus. Tonight the beautiful Pleiades star cluster lies 15 degrees above Venus. For a few evenings around April 11, both Venus and the Pleiades cluster will simltaneously fit within the field of view of binoculars. By then, Saturn will be nearly gone.
The Moon is Full today at 5:49 p.m. EST, and for much of U.S. rises very near the time of sunset. Observers in northeastern states who have flat horizons toward east and west have the best chance to see Sun and Moon simultaneously just before sunset. About one-and-a-half hours after sunset, watch for the rising of Spica in ESE, about 12 degrees below the Moon. Brilliant Mars rises about another hour later, nearly 18 degrees lower left of Spica. On Thursday evening, the Moon will appear 6 degrees north (left) of the star, and late on Friday evening about 4 degrees upper left of Mars.
Tonight's Blue Moon (second Full Moon within a calendar month) is the last until November 2001 (or October 2001 for the Central time zone and farther west). Not until January and March of 2018 will there again be two Blue Moons within the same year.
No programs at Abrams Planetarium Easter Sunday, April 4. Public skywatching nights at Michigan State University Observatory will be held on selected Friday and Saturday evenings, 9-11 p.m., weather permitting: April 23, 24, May 21, 22, June 18, 19, and July 16, 17.