A sample Sky Calendar for this month is available over the Internet. It can be viewed via a World-Wide Web browser such at Netscape or Mosaic, directly at URL:
http://www.pa.msu.edu/abrams/skycal.html
If you would like a printed sample, send a long, self-addressed stamped envelope to:
September Sky Calendar
Abrams Planetarium
Michigan State University
East Lansing, MI 48824
Each month, the Department of Physics and Astronomy at Michigan State University also makes Skywatcher's Diary available over the Internet. It can be accessed via a World-Wide Web browser such as Netscape or Mosaic, 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
September and early October offer a visual feast of celestial phenomena. Bright Jupiter is in south at dusk in September. Saturn in late September rises at sunset and is up all night. Telescopes show Saturn's rings tipped just over 4 degrees from edge-on with their south face in view. Comet Hale-Bopp, visible in binoculars at nightfall and detectable with unaided eye from very dark sites, is on track to become next year's Great Comet. Venus in early September and Mercury in early October reach their highest positions in the morning sky for this year. Venus and Mars appear within 3 degrees of each other in September's first week, and spread to 13 degrees apart by month's end. September's Harvest Moon undergoes total eclipse in close company with Saturn; totality can be witnessed in all North America except western Alaska. The end of September and early October bring us four naked-eye planets (all except Jupiter) simultaneously visible in morning twilight. A daily morning skywatch will be especially rewarding October 1-11, giving a view of Venus passing Regulus Oct. 1-6 (they're closest on Oct. 3 and 4), and the waning crescent Moon sliding down past Mars, Regulus, Venus, and Mercury October 7-11.
For the total lunar eclipse on Sept. 26, most North Americans have ringside seats! What colors do you see on Moon during totality? Refer to the article on pp. 68-71 in September Sky & Telescope for some observing projects, or check their eclipses site at: http://www.skypub.com/eclipses/eclipses.html
Look for Saturn glowing strikingly just 2 degrees from the shadowed Moon. Listen for the sounds of insects --which you can hear on most any night this time of year, not just during a lunar eclipse. During a total lunar eclipse in Aug 1989 we heard Katydids. Hawthorne called the rhythmic chirping of Snowy Tree Crickets "an audible stillness" and added that "if moonlight could be heard, it would sound like that." -- Crickets and Katydids, Concerts and Solos, by Vincent D. Dethier. West of longitude 114 degrees to Coast, Moon rises with eclipse already underway; will anyone there see Sun in west and partially eclipsed Moon in east, simultaneously?
Total lunar eclipses can often be remembered by some unique or unusual feature. In December 1963, the eclipsed Moon was so dark and faint that it could be glimpsed only by knowing where to look, using averted vision. The presence of aerosols in our stratosphere, resulting from a major volcanic eruption in Indonesia, had blocked most of the sunlight from getting through our atmosphere to the Moon. Unusually dark eclipses in 1982, 1992, and 1993 followed major eruptions in Mexico and the Phillipines.
In April 1968, our planetarium staff, observing from a dark rural area, saw a beautifully colored eclipsed Moon in close conjunction with Spica. The edge of the Moon nearest to Spica was bluish in color, as if the star were illuminating the Moon. The opposite limb of the Moon, deepest within Earth's shadow, was a dark chocolate-brown, and the rest of the Moon was red-orange.
We'll always remember August 16, 1989 as the date of the "Katydid total eclipse", because as we watched the event from outside MSU Observatory, these insects of late summer and early fall were scraping their raucous "love songs" from the treetops.
The total lunar eclipse on Thursday, September 26 may combine some aspects of those of 1968 and 1989, because this year's event also has a bright companion "star", Saturn, only 2 degrees away. The off-center location of the Moon within Earth's shadow usually produces good gradients of darkness and color, especially at start and end of totality. But at mid-totality, 10:54 p.m. EDT, the Moon will be closer to the shadow center than in 1968, so this eclipse may be darker and less colorful than the one in 1968. This time, the Moon's brighter edge will be the northern limb, the side away from Saturn.
For our September Sky Calendar, which includes an illustration depicting the various stages of this eclipse and an evening sky map, point your Web Browser to:
http://www.pa.msu.edu/abrams/skycal.html
This month's eclipse, as in 1989, occurs during the season for Katydids, provided we haven't had a hard frost by Sept. 26. We also expect to hear the rhythmic chirping of Snowy Tree Crickets. We've been hearing these two species since mid-August (both started later than usual, perhaps because of a cold spring); for a checklist of Michigan Orthoptera, set your Web browser to:
http://insects.ummz.lsa.umich.edu/fauna/Michorthops.html
Locating Comet Hale-Bopp in September: Using our all-sky map, September Evening Skies, locate the 2.1-mag star Rasalhague, or Alpha in Ophiuchus, 2/5 of the way from Vega to Antares. It's also 2/5 of the way from Altair to Arcturus, but a little south of a line connecting them. Alpha Oph, marking head of Ophiuchus, the Serpent-bearer, stands out as the brightest star within the giant quadrilateral Vega-Altair-Antares- Arcturus. Next, find 2.8-mag Beta 8 degrees lower left of Alpha, and 2.4-mag Eta Oph 14 degrees upper left or above Antares and 22 degrees below Beta Oph. The 4.5-mag star SAO141665 is nearly halfway from 2.8-mag Beta Oph toward 2.4-mag Eta Oph, and 11 degrees from each. At nightfall on Sept 1, Comet Hale-Bopp is easily seen in binoculars 3.2 degrees left of SAO141665 and 1.6 degrees upper right of Mu Oph. On Sept 15, Comet H-B is 1.4 degrees left of SAO141665 as shown on map. During Sept 25-Oct 2, comet lingers about 0.8 degree from SAO141665, and passes due east (upper left) of it Sept 29.
Prospects for Comet Hale-Bopp: Comet expert and Michigan State University Alumnus Charles S. Morris at NASA's Jet Propulsion Laboratory has issued a brightness forecast for Comet Hale-Bopp from now until its closest approach to Earth and Sun in late March next year, and it is good news! Since Earth is temporarily receding from Comet Hale-Bopp until late October, the comet brightens slowly for now, to mag. 5 in September and to mag. 4 sometime in November. At the turn of the year, as the comet sinks into the western twilight glow and emerges into the eastern morning sky, Morris predicts it will glow between 3rd and 2nd magnitude. If the comet is bright enough, observers at mid-northern latitudes may be able to follow it without interruption as it passes 28 degrees N of Sun on December 30.
Comet Hale-Bopp in 1997: From January well into March, Comet Hale- Bopp is expected to brighten in E to NE predawn sky as it closes in on both Earth and Sun. On March 21 it once again passes solar conjunction, this time 45 degrees to the Sun's north. For several days, comet will appear both in NE at dawn's first light and in NW at nightfall. A few days later, on a moonless evening in late March, Hale- Bopp is expected to peak in brightness, between mag. -0.5 and -2.0, according to Morris. But he cautions, quoting from his very good friend, comet discoverer-observer, and writer David Levy: "Regarding people who insist that [Hale-Bopp will be very bright in 1997]: Comets are like cats. They have tails, and they do precisely what they want."
For more on Hale-Bopp: http://encke.jpl.nasa.gov/hale_bopp_info.html Also check Sky & Telescope's site: http://www.skypub.com/
In the eastern morning sky for over three hours before sunrise, Venus and Mars are just 3 degrees apart all this week; they appear closest at midweek, as Venus passes within 2.9 degrees south of Mars.
Total Eclipse of the Harvest Moon, September 26, 1996 Last April 3, a total eclipse of the Moon was well seen only from eastern U.S. This Thursday, a greater portion of the country will be in good position to view the year's second total lunar eclipse. A striking feature will be the presence of Saturn only about 2 degrees from the eclipsed Moon. Not since April 12, 1968 have North Americans seen the totally eclipsed Moon so close to a bright object (it was Spica), and not again until February 20, 2008 will the Moon in total eclipse again appear within a few degrees of a bright object, actually two objects, Saturn and Regulus!
The umbra, or dark central core of Earth's shadow, as projected on the Moon during lunar eclipse is usually a deep reddish orange or rusty color, from sunlight which passes close to Earth and is bent, by our atmosphere, into the shadow. The color isn't usually noticed until most of the Moon is covered by the umbra. (more)
The entire umbral eclipse, including totality, will be above the horizon for all of the U.S. east of longitude 114 degrees W (northwestern Montana through east boundary of Nevada and western Arizona). West of those locations to the West Coast, the Moon will rise with the umbral eclipse already in progress. Near longitude 114 degrees W and a little farther west, from places with good horizon views, it may be possible to observe Sun and partially eclipsed Moon simultaneously, a few minutes after the Moon begins to enter the umbra. (If you make such a sighting, please send us a report!) From Hawaii and western Alaska, the Moon rises during the closing partial phases, after totality is over.
From the U.S. West Coast and possibly as far east as Salt Lake City, the Moon may disappear in twilight as the eclipse becomes total, and reappear, still in total eclipse, as the sky darkens.
LUNAR ECLIPSE ON NIGHT OF SEPTEMBER 26-27
Moon enters umbra 9:12 p.m. EDT West Coast not visible Total eclipse begins 10:19 p.m. EDT 7:19 P.M. PDT Deepest eclipse 10:54 p.m. EDT 7:54 P.M. PDT Total eclipse ends 11:29 p.m. EDT 8:29 P.M. PDT Moon leaves umbra 12:36 a.m. EDT 9:36 P.M. PDT
A deep, possibly very colorful partial eclipse, 92% in shadow, will be visible in all U.S. except Hawaii and Alaska, on the night of March 23, 1997. The next total lunar eclipse for us will be visible throughout the Americas and Hawaii on January 20, 2000.
http://www.pa.msu.edu/abrams/skycal.html
Eclipse observing at MSU
About an hour before sunrise for the next week, four planets are visible simultaneously. Begin with Venus in the east. On Monday morning, Mars is 13 degrees upper right of Venus, while Regulus and Mercury are respectively 4 deg and 24 deg to Venus' lower left. Turn around to spot Saturn about to set a few degrees south of due west. In sequence from east to west, note the beautiful alignment of Mercury, Regulus, Venus, Mars, Pollux, Aledbaran, Moon, and Saturn. All appear within the celestial beltway known as the zodiac, which appears nearly vertical in the predawn sky in late summer and early fall.
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