Sky Calendar
Abrams Planetarium
Michigan State University
East Lansing, MI 48824
A sample *Sky Calendar* of a past month is available over the Internet. It can be accessed via a World-Wide Web browser such at Netscape or Mosiac, directly at URL:
http://www.pa.msu.edu/abrams/novskycal.html
The Department of Physics and Astronomy at Michigan State University continues to make *Skywatcher's Diary* available over the Internet. It can be accessed via a World-Wide Web browser such as Netscape or Mosiac, directly at URL:
http://www.pa.msu.edu/abrams/diary.html
The Skywatcher's Diary is also available via anonymous ftp at: www.pa.msu.edu in the directory pub/swd/
Dawn skywatchers can see bright Jupiter low in SE to SSE an hour before sunup. Look for a waning gibbous Moon near the bluish first- magnitude star Spica March 8, a crescent Moon near Jupiter March 14, and to Jupiter's lower left on the next three mornings.
Our first view of an evening crescent Moon occurs low in the west in early dusk on Mar. 20, with the Moon climbing just lower left of brilliant Venus on Mar. 22. Moon can be found closely above Aldebaran on the evening of Mar. 24. There's a total lunar eclipse visible from eastern U.S. in the early evening on Wednesday, April 3. For details on the eclipse, see entries for March 30, April 1, and April 3 in Skywatcher's Diary, below.
Also on Monday before dawn, locate bright Jupiter low in SE. Binoculars show a pair of 5th-magnitude stars, Nu-1 and Nu-2 Sagittarii, 7 arcminutes and 21 arcminutes to Jupiter's lower left, and Ganymede, Jupiter's brightest moon, and fainter Europa, much closer in on the same side. Another Jovian moon, Callisto, appears 6 arcminutes to Jupiter's upper right. In the next few mornings, watch for changes as Jupiter's orbital motion carries the planet eastward past the two stars. On Wednesday morning, seen from western U.S., Jupiter will occult or cover one of the two stars.
One to 1-1/2 hours before sunup on Tuesday, a telescopic view will show Jupiter accompanied by as many as 6 bright objects. Can you tell which four are the real moons, and which two are imposters? Appearing farthest out of the six, the star Nu-2 Sagittarii appears 11 arcminutes east of Jupiter, to its lower left in the sky as seen through binoculars. It seems in alignment with Jupiter and the "real" moons because Jupiter will in fact occult, or cover, the star as seen from western U.S. on Wednesdady morning. On Tuesday, Europa appears close in on the same side as Nu-2, and Callisto appears farthest out on the opposite (west) side of Jupiter, 7 arcminutes from the planet. The star Nu-1 Sagittarii is an obvious imposter, out of line with the other bodies and 3 arcminutes to the southwest of Jupiter. Jupiter and its moons always appear in a nearly straight line because we view the moon's orbits nearly edge-on.
On Wednesday, one to 1-1/2 hours before sunup, a telescope shows three satellites west of Jupiter, and a star, Nu-1 Sagittarii, even farther west and out of line with the other bodies. Close to Jupiter's east lies Io, the innermost of the four satellites discovered by Galileo in 1610. As seen from the western U.S., the star Nu-2 Sgr will be occulted by Jupiter, disappearing on the planet's east limb around 5:05 a.m. PST, and reppearing on the west limb around 6:34 a.m. PST.
If you sky isn't very dark even when it's very clear and dry, your site may be suffering from light pollution. If you're interested in helping to solve this problem, join International Dark-Sky Association, 3545 N. Stewart Ave., Tuscon AZ 85716. Memberships begin at $20 per year. This unique organization is worthy of support by all who value the beauty of the night sky.
IDA has a Homepage on the World Wide Web, at: http://www.darksky.org/~ida/index.html
A comet is coming! The discovery of Comet Hyakutake C/1996 B2 was reported Jan. 31. Preliminary calculations indicate that Comet Hyakutake may become bright as it passes within 10 million miles of Earth two weeks from now. Then the comet is expected to fade some, then rebrighten in late April before disappearing into the solar glare on approach to perihelion 21 million miles from the Sun on May 1. Keep in mind that predictions of comet brightnesses are very uncertain!
The predictions about Comet Hyakutake appearing in the rest of this month's Skywatcher's Diary are based on information available as of February 9, 1996. We will know more by this date in March. For an update from the Internet, set your Web browser to: http://encke.jpl.nasa.gov/whats_visible.html
For up-to date predictions of this comet's position and brightness: http://encke.jpl.nasa.gov/eph/96B2.2000
An hour before sunup on Wednesday, the Moon in ESE appears as a fat crescent, distinctly less than half full. The bright "star" 11 degrees to the Moon's lower left is actually Jupiter. Before dawn brightens, look below the Moon for the eight stars of 2nd and 3rd magnitude which form the Teapot in the constellation Sagittarius. Look again on Thursday.
As that date approaches (about March 27), use binoculars if necessary to help you spot Sirius over your marker. (Be sure to prefocus your binoculars on a distant object, such as the Moon.) If the sky is very clear, you may be able to spot it with the unaided eye.
Saturday, March 16, cont'd): One more easy chance to see the old Moon: 45 minutes before sunrise on Sunday, look very low, between E and ESE, for the very thin crescent. For Michigan skywatchers, the Moon will then be nearly 48 hours before New.
Today Saturn is in conjunction with the Sun, and is invisible on Sun's far side. By the end of April, Saturn will emerge into view in the eastern morning sky.
Today, and not the equinox date of March 20, is when the duration of day and night come closest to exactly 12 hours each. Every year we get telephone calls asking: Why is the "equinox" three days early? One contributing factor is refraction by Earth's atmosphere, which lifts the Sun's image when it's near the horizon, hastening sunrise and delaying sunset. Another factor arises from the definition of sunrise and sunset: When the *top* of the solar disk, rather than its center, appears on an ideal, flat horizon. In total, these two factors lengthen the day at mid- latitudes by about 9 minutes.
This special cycle of the Moon will culminate two weeks from tonight, with a total lunar eclipse visible from eastern U.S. on April 3. See Skywatcher's Diary entries for March 30, April 1, and April 3, below.
Comet Hyakutake by now may have brightened to 2nd magnitude, and it's now visible from late evening through rest of night. Four hours after sunset, locate the Big Dipper high in NE, then its curved handle will lead you to the bright star Arcturus in the east: "Follow the arc to Arcturus." Using binoculars, look for a fuzzy ball of light 10 or 11 degrees below Arcturus. That's the comet, now just 14 million miles from Earth and closing! On March 25, Comet Hyakutake will pass within 10 million miles of our home planet. A finder chart is available here.
As it sweeps rapidly by Earth, Comet Hyakutake is now changing its position against background stars by over 10 degrees from one night to the next. Three or four hours after sunset, locate Arcturus in east (see March 21), and the 2nd-magnitude star Izar 10 degrees to its left. Tonight the Comet may be a magnitude 1.5 fuzzball 8 degrees lower left of Arcturus and 4 or 5 degrees lower right of Izar. Binoculars may give the best view. Arcturus, Izar, and four additional stars to the left of Arcturus complete a kite-shaped figure lying on its side, comprising the constellation Bootes, the Herdsman.
Here's where to look for the comet tonight. Three hours after sundown, look for bright Arcturus in the east, then find 2nd-magnitude Izar 10 degrees to its left. Tonight the comet is 10 degrees upper left of Izar and about 3 degrees below 3rd-magnitude Gamma in Bootes, one corner of the kite-shaped figure comprising the main stars of the constellation of the Herdsman or Bear Driver. Binoculars may give the best view of the comet. A finder chart is available here.
The comet may appear as a fuzzball shining at first magnitude tonight, but that is the *total* of all its light, which is spread out over an area of sky probably appearing at least half a degree across, as big as the angular diameter of the Moon. Since the light is spread out over a large area, the comet, even if first magnitude, may not appear all that bright to the eye, especially from places where the sky isn't very dark.
Another fact to keep in mind: These predictions of the comet's positions were based on observations made during the first week after the comet's discovery, and the orbit hadn't been well determined yet. Especially on these nights when the comet is very close to Earth, the comet's positions could be several degrees off!
Early this week, Comet Hyakutake may reach its greatest brightness, at perhaps first magnitude, but because much of its light is spread out over a large area, the "coma", or head of the comet, it will not appear as bright as a star of the same magnitude. Tonight and tomorrow, the comet passes within 10 million miles of Earth. In the late evening, look about 8 degrees lower left of the end of the handle of the Big Dipper.
After nightfall on Monday, March 25, locate the Little Dipper in the north. Kochab, or Beta in Ursa Minor, is the brightest star in the bowl of the Little Dipper, 17 degrees from and matched in brightness to Polaris, the North Star, at the end of the Little Dipper's handle. Tonight, the comet appears about 4 degrees upper right of Kochab.
After nightfall, look for the comet about 5 degrees upper right of Polaris, the North Star. A finder chart is available here.
Lunar eclipse a week from tonight! See March 30, April 1, and April 3.
The Lunar Eclipse of Wednesday, April 3: What you can see depends on your location: The farther east you are in the U.S., the better; if you're too far west, you won't see it at all!
The Moon on Wednesday, April 3 will rise in total eclipse from the Great Lakes, Southeast, Mississippi River, and Gulf Coast. But in these regions it would be well not to have high expectations of what might actually be seen: The disk of the Moon in total eclipse is too dim to be seen in bright twilight, and within the U.S. it's likely to be seen only from eastern states, after the sky has darkened. A total eclipse on September 26 will occur later in the evening and be more widely visible.
What you'll see of the eclipse on April 3 depends on your location. From New England, New Jersey, and eastern New York state, Moon rises already in partial eclipse, and all later stages, including totality, happen with Moon above horizon. For rest of eastern and central U.S. westward to Minnesota and eastern third of Texas, the Moon rises invisibly in total eclipse. In mid-Michigan, for example, where the Moon rises in the middle of totality, the Moon won't be seen until it begins to emerge from Earth's shadow, at 7:53 p.m. EST. Still farther west, from the Dakotas and rest of Texas west to central Montana and western Arizona, Moon rises during the terminal partial stages of the eclipse. Still farther west, Moon rises after the umbral eclipse is all over. More, with times, on Monday.
Tonight, Venus appears at its farthest from the Sun this time around, 46 degrees. Venus sets four hours after sundown. Not until the year 2004 will Venus again be so favorably placed in the evening sky. Seen through a telescope these evenings, Venus is now about one-half illuminated.
At nightfall during March 31-April 5, Comet Hyakutake will be within 2 to 6 degrees of the 2nd-magnitude star Alpha in Perseus. (Locate this star in NW, to upper left of the "W" of Cassiopeia and upper right of Venus.) Starting April 5, the Moon won't interfere. A finder chart is available here.
Monday,April 1 During the lunar eclipse on Wednesday, Apr. 3, the farther east you are, the more of the eclipse you'll see; the best places in U.S. to view totality are New England, New Jersey, eastern New York, and the Atlantic Coast down to North Carolina, after the sky has darkened enough to allow observation of the dimly lit eclipsed Moon. Depending on the darkness of Earth's shadow on the Moon, mid-totality at 7:10 p.m. EST may be visible only from eastern New England. If the Moon at mid- eclipse is uncharacteristically bright, it might be seen over more of northeastern U.S.
Totality ends at 7:53 p.m. EST. By then evening twilight is over (the sky is dark) in eastern New England and the eastern tip of Long Island, and twilight is nearly over in North Carolina's Outer Banks and in southeast Florida. The farther west you are as totality ends, the brighter the sky will be, and harder it will be to see the still-dimmed Moon. From mid-lower Michigan to the Mississippi-Alabama coast, totality ends in mid-twilight, with the Sun 9 degrees down and the Moon 8 degrees up; unless the eclipse is unusually bright, totality will be noted only by the Moon's absence. There and farther west to Minnesota and east Texas, the Moon probably won't be seen until it begins to emerge from the umbra at 7:53 p.m. EST (6:53 p.m. CST). Still farther west, from the Dakotas and rest of Texas west to central Montana and western Arizona, the Moon rises during the terminal partial stages of the eclipse. The Moon is completely out of the umbra by 8:59 p.m. EST (7:59 p.m. CST, 6:59 p.m. MST). Sorry, if you're even farther west (west of a line from central Montana to western Arizona), the umbral eclipse is completely over before moonrise! Wait for this year's second lunar eclipse, on Sept. 26. It will occur later in the evening, so will be in better view, higher in the sky for all skywatchers across the continental U.S.
If you're not too far west in the U.S., remember to observe Wednesday evening's lunar eclipse. For details, see March 30, April 1, and April 3.
Our session will begin at 7:30 p.m., at the *east* end of the top level of the parking ramp behind Abrams Planetarium (that's the end farther from the Planetarium and closer to the Moon). While we're waiting for the Moon to appear, we'll watch the early spring stars come out, enjoy telescopic views of Venus in its "half moon" phase, binocular views of Venus near the Pleiades star cluster, and of Comet Hyakutake below the Alpha Persei cluster. The session will close with the Moon's complete emergence from Earth's shadow at 8:59 p.m. EST.
For details on the lunar eclipse from other parts of the country, see March 30 and April 1.
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