At sunset, the Moon, two-thirds full, is low in SSE. Mars and Venus are both 7° from Sun today and will reach solar conjunction on Oct. 23 and 27. Faint Mars sets soon after the Sun and is hopelessly lost in bright twilight, but if you use binoculars 20 minutes before sunrise tomorrow, provided the sky is very clear, you might still catch Venus about 2° up and a degree or two south of due east.

Programs at Abrams Planetarium today:

At 2:30 p.m.: Opening of our Family Show, The Sky Above Mister Rogers' Neighborhood
Come and explore familiar objects in the sky with Mister Rogers and your favorite characters from the Neighborhood of Make-Believe.

At 4:00 p.m.: Final showing of Sky Preview 2006-2007
A live show highlighting the current sky, the Moon's unusual wanderings in coming months, and a preview of planet gatherings until mid-2007. Included are two total lunar eclipses and a spectacular midyear evening pairing of Venus and Saturn.

An hour after sunset the four brightest objects visible, in order of brilliance, are the Moon in SSE; Jupiter very low in WSW; Arcturus in W; and Vega, just WSW of overhead.

An hour before sunrise on Wednesday, the five brightest objects visible, in order of brilliance, are Sirius, the Dog Star, in SSE; Capella, the Mother Goat Star, just WNW of overhead; Rigel, Orion's foot, in S to SSW; Procyon, the Lesser Dog Star, in SE; and steadily shining Saturn, in E to ENE.

An hour after sunset, the Moon is in ESE to SE. Look for the first-magnitude star Fomalhaut, Mouth of the Southern Fish, 20° to Moon's lower right. About two minutes later, at 8:16 p.m. EDT in East Lansing, Capella in NNE and Fomalhaut in SE are the same distance above the horizon, about 4°.

At sunset (7:12 p.m. in East Lansing) the Moon is only 7° up and 9° south of due east. Within half an hour, find Jupiter 10° up in SW to WSW, and, using binoculars, try to see Mercury within 15° lower right of Jupiter. From the latitude of East Lansing, Mercury is then just a degree or two above the horizon. From southern states it is higher and easier to see. Mercury will close to within 10° lower right of Jupiter on Oct. 10, and then within 5° on Oct. 16, but Mercury won't gain much altitude, as Jupiter is sinking lower each evening.

On Friday 1½ hours before sunrise (or 6:11 a.m. EDT in East Lansing), face east to find Saturn with Regulus, heart of Leo, 8° below and a little left. (They'll close to within 5° when Saturn begins retrograde in early December.) The Moon is 7° up in W and sets within 45 minutes later. Does the Moon seem unusually large as it sets Friday morning? In fact it's at perigee, closest to Earth, at a distance of 222,084 miles at 10 a.m. EDT.

From East Lansing, MI the Full Moon rises 7 or 8° north of east at 6:54 p.m. EDT, just 16 minutes before sunset. From a place with unobstructed views toward opposite horizons, it's possible to observe Sun and Moon simultaneously for a few minutes around 7:00-7:05 p.m. EDT. Just nine hours after perigee, the Moon may seem unusually large at its rising. (But even when it's far from Earth, it still seems bigger when it rises or sets compared to when it's high in the sky on the same night, even though measurements on photographs prove the reverse is true.) From East Lansing (longitude 84.5° west, latitude 42.7° north), the Moon reaches its highest point in the sky for tonight, 54° up in the south, at 1:28 a.m. EDT on Saturday morning, and sets 13° north of west at 8:17 a.m., about 35 minutes after sunrise.

Our Fall Feature presentation, opening at Abrams Planetarium at 8:00 p.m. tonight:

The Last Question
Celebrating the 50th Anniversary of this classic Isaac Asimov short story and narrated by Leonard Nimoy, this show recounts the running down of the Universe — the relentless increase of entropy — brought to life under the planetarium dome. (presented Fridays and Saturdays at 8:00 p.m., and Sundays at 4:00 p.m.)

Our Family Show, The Sky Above Mister Rogers' Neighborhood,
continues Sundays at 2:30 p.m.

For Abrams Planetarium show information, call (517) 355-4672.

Seen from East Lansing, MI, the Moon, just past Full, rises 17° north of east at 7:19 p.m. EDT, just 10 minutes after sunset. On Sunday morning, the Moon sets in WNW at 9:40 a.m., nearly two hours after sunrise.

From East Lansing, the Moon rises 26° north of east at 7:47 p.m. this evening. Wait an hour, then using binoculars, look for the Pleiades star cluster rising 17° to the Moon's lower left. The Moon will occult, or cover, several stars of this cluster on Monday night. We'll have more on this event tomorrow.

Tonight from East Lansing, the Moon rises 33° north of east at 8:21 p.m. EDT, still before the end of evening twilight. An hour later, the Pleiades cluster is easily visible in binoculars about 2 to 3° to the Moon's lower left. From just before midnight until nearly 2 a.m. the Moon covers and uncovers several of the brighter stars of the cluster. Here is a chronological listing of the brightest events visible through a telescope. (Times are for East Lansing. DB = disappearance of star behind the leading bright edge of the Moon. RD = reappearance at the trailing dark edge of the Moon.) Electra (mag. 3.8) DB 11:58 p.m.; Maia (mag. 4.0) DB 12:39 a.m.; Merope (mag. 4.3) DB 12:43 a.m.; Electra RD 1:00 a.m.; Merope RD 1:07 a.m.; Alcyone (mag. 3.0) DB 1:13 a.m.; Maia RD 1:30 a.m.; and Alcyone RD 1:52 a.m.

Note that the southern limit for the occultation of Alcyone, brightest member of the Pleiades, is a line from southeast Texas to western NY State, crossing the SE corner of Lake Ontario to just south of Montreal and to the northern tip of Maine. So much of the eastern U.S. will not see an occultation of this star, but a narrow miss instead. The southern limit of the occultation of Merope goes from the tip of Mexico's Baha peninsula through southeast Texas, and extreme southeast Michigan, into Canada. In a very narrow track along that line, a "graze" may be seen, during which the star disappears and reappears from behind mountains on the Moon's southern limb. Downtown Detroit sees a very short occultation of Merope, from about 12:50 a.m. until 1:01 a.m. For maps of visibility and times of events for other cities, see Occultations of the Brightest Pleiads for North America, at http://www.lunar-occultations.com/iota/2006plnam/pleiadna.htm

East Lansing sees the Moon rise tonight at 9:03 p.m. EDT, some 38° north of east and 11 or 12° lower left of the Pleiades. In about another hour watch for the rising of Aldebaran, eye of Taurus, 10° to Moon's lower right. By 1½ hours before sunrise on Wednesday, the three-quarters illuminated gibbous Moon is very high in SW, with Aldebaran 12° below and the Pleaides 16° to Moon's lower right. Elnath, the tip of the Bull's northern horn, is 6° to Moon's upper left. With daylight saving time in effect, these dark mornings are convenient for following the Moon's eastward progress against the bright stars of the zodiac. From now until October 20, watch the Moon go past Castor and Pollux the Gemini Twins, Saturn, Regulus the heart of Leo, and on into Virgo.

Tonight from East Lansing, this month's northernmost moonrise occurs about 9:54 p.m. EDT, some 40 to 41° north of east and about 3° lower left of Elnath, the brighter, northern horn of Taurus the Bull. The bright star 19° to Moon's upper left is Capella, the Mother Goat. The Moon climbs highest at 6:14 a.m. EDT on Thursday, when it is just over 14° south of overhead, and sets at 2:33 p.m. that day, some 40-41° north of west. From moonrise Wednesday evening until moonset Thursday afternoon spans 16 hours 39 minutes, the longest interval the Moon is above the horizon (in East Lansing) during this year of maximum inclination of the Moon's orbit to Earth's equator. (From places farther north, the Moon is up even longer on Oct. 11-12, even though it doesn't get as close to overhead.) The inclination of the Moon's orbit to Earth's equator varies from nearly 29° to just over 18° and back again in a cycle lasting almost 19 years. So the next time the Moon ranges extremely far north and south will be in the year 2025.

From East Lansing tonight at 10:55 p.m., the Moon rises 40° north of east, some 25° below Capella. In about another 1½ hours, the Gemini Twins Castor and Pollux, 4½° apart, are 11 to 13° to Moon's lower left. By 1½ hours before sunup on Friday (or 6:19 a.m. EDT in E. Lansing), the Moon, very high in SE, pulls to within 10° west of Pollux, the brighter Twin.

At 12:01 a.m. tonight (Saturday morning) in East Lansing, the Last Quarter (half full) Moon rises 37° north of east, only 2 to 3° lower right of Pollux. By 1½ hours before sunrise on Saturday, the Moon is high in ESE to SE, 3 or 4° below Pollux.

About 45 minutes after sunset, look for Jupiter only 5° up, about 30° south of west, and Arcturus about 20° up, just north of due west. As the sky darkens a bit, look for Antares 19° to Jupiter's upper left. In 2007, Jupiter will pass about 5° from that star twice, in January in the morning sky, and in August in the evening.

Today there is a compact gathering of two planets and a star. But alas, the Sun is within the triangle formed by Venus, Mars, and Spica, so none of the three bodies, all within 4° of the Sun, is visible. On Monday 1½ hours before sunrise (6:22 a.m. EDT in E. Lansing), a crescent Moon just over one-quarter full is high in ESE with bright Saturn between 2 and 3° lower right. Regulus, heart of Leo, is 7° lower left of Saturn. The same time on Tuesday morning, the Moon will be 3° lower left of Regulus. A telescope shows lunar surface features especially well near the Moon's terminator (day-night boundary, where the Sun is now setting), and the rings of Saturn, now tipped about 13° from edge-on.

Using binoculars, try to catch Mercury on this date of its greatest elongation 25° from the Sun. But conditions are very poor for observers at middle and high northern latitudes. First find Jupiter very low, about 30° south of west 35 minutes after sunset, and then scan the horizon 5° lower right of Jupiter. This is a poor appearance from East Lansing: Even though Mercury is 23° left of the Sun, it is only 8 or 9° higher than the Sun and so sets early, in a bright sky.

On Wednesday 1½ hours before sunrise (or about 6:25 a.m. EDT in East Lansing), find bright steady Saturn about 40° up in ESE, fainter Regulus 7° to its lower left, and a beautiful slender crescent Moon, with earthshine on its dark side, 15° lower left of Regulus. Note Denebola, tail of Leo, 13° to Moon's lower left. On Wednesday morning the Moon's disk appears about one-eighth sunlit, seven-eighths dark but illuminated by reflected earthlight - a beautiful sight well worth the trip outside on a crisp, clear autumn morning! Sirius, the brightest star, passes due south (in East Lansing) less than 31° above the horizon, at 6:36 a.m. EDT.

Using binoculars 30 minutes after sunset (or 7:21 p.m. in East Lansing), look for Jupiter very low about 30° south of west, with Mercury 4.3° directly below.

The Moon is lower each morning as it approaches conjunction with the Sun (called New Moon) this weekend, overnight Saturday to Sunday. On Thursday morning 1½ hours before sunrise (or 6:26 a.m. EDT in East Lansing), find the thin 7-percent crescent 10° up in the east and 13° lower right of Denebola, Leo's tail. At the same time on Friday, the even thinner Moon will have just risen.

Last chance to see Moon in morning sky this month: On Friday an hour before sunrise (or 6:57 a.m. EDT in East Lansing) look for the very thin 3-percent crescent only 5° up, 11° south of east. Binoculars show the 3rd-mag. star Gamma in Virgo 4 or 5° to the Moon's left.

For seven consecutive days beginning tonight, about 30 minutes after sunset, if you can find Jupiter very low about 30° south of due west, binoculars may show Mercury lingering 3.9° to its lower left. But both are getting lower each evening. This long-lasting pair is easier to see from southern states.

During Saturday's predawn darkness hours, look for the swiftly moving Orionid meteors, particles from Halley's Comet, near their peak in a dark moonless sky.

New Moon occurs tonight at 10:14 p.m. PDT (1:14 a.m. EDT on Sunday morning). The first easy chance to see the Moon from northern U.S. will be very soon after sunset on Tuesday evening.

From a very dark place these moonless mornings, just before twilight begins (1.6 hours before sunrise from the latitude of East Lansing, MI), look just south of due east for the Zodiacal Light, a huge, softly luminous cone of light, broadest and brightest not far above the horizon, and tapering upward toward Regulus and Saturn, and possibly beyond them. The glow is from sunlight reflected off dust particles (originating from comets and from collisions of asteroids) in the plane of the solar system.

Mars passes conjunction on the Sun's far side overnight tonight, and Venus does the same 4½ days later, on Fri. Oct. 27. Owing to the relative angular speeds of Venus, Earth, and Mars in their orbits around the Sun, Mars will emerge into the morning sky in coming months, and Venus will emerge into the evening sky. See if you can explain this fact with a diagram of the solar system as seen from above. In the middle of this week, Earth-Sun-Venus-Mars lie in a nearly straight line. Seen from above the solar system, all the planets revolve counterclockwise around the Sun, with inner planets going faster: Venus averaging 49° per month, Earth 30°, Mars 16°. Earth rotates on its axis in the same direction, counterclockwise, causing the rising and setting of the Sun, Moon, planets, and stars. Currently, Venus and Mars rise and set with the Sun. Advance the three planets forward in their orbits two months, and then list the risings and settings of Sun, Venus, and Mars in chronological order over a 24-hour day, for example, from sunset to sunset.

Earliest chance to see the young Moon within the U.S. tonight is from south Florida within 25 minutes after sunset, when the 3-percent crescent, age 42 hours, is 3 to 4° up in WSW. Mercury and Jupiter are 4° apart, 5 to 7° above the Moon. Other places where the thin crescent may be seen are in the Southwest U.S., from south Texas to southern California. From Palm Springs, CA 20 minutes after sunset (or 6:23 p.m. PDT), the Moon is 30° south of west and less than 3° up, so a vantage point with an unobstructed view must be chosen carefully. There the Moon at that time is just over 44 hours old. Hawaii will have a much easier time spotting the gathering of Jupiter, Mercury, and the 47-hour old Moon, all with unaided eye, about 35 minutes after sunset.

From East Lansing 30 minutes after sunset (or 7:12 p.m. EDT), the Moon is very low, just 3° up and 40° south of west, but is thick enough — a 7-percent crescent — to be seen easily if the sky is very clear and if your view isn't obstructed. Using binoculars, can you spot Jupiter about 10 or 11° to Moon's upper right, and Antares 8° to Moon's upper left? Mercury, still within 4° to Jupiter's lower left, is getting hopeless from northern U.S.

Half an hour after sunset from East Lansing (or 7:10 p.m. EDT), the crescent Moon, one-eighth full, is about 8° up in SW. As the sky darkens a bit, try for Antares 5° to Moon's lower right, and Jupiter another 17° lower right of Antares.

From East Lansing, today's southernmost Moon passes due south, less than 18° up, at 5:01 p.m. EDT. It's 20 percent full and 53° east of the Sun. At 8:00 p.m., using binoculars, look for 3rd-mag. Gamma Sagittarii, tip of the Archer's arrow and tip of the spout of the Teapot, just 4° upper left of the Moon. Moonset is about 9:09 p.m., 41° south of west.

Today from East Lansing, MI, the Moon passes due south at 5:58 p.m. EDT, just over 18° up, a little higher and nearly an hour later than yesterday's time. At 8:00 p.m., just before nightfall, the Moon, a 30-percent crescent, is 13° up in SSW, and inside the asterism known as the Teapot. Its two brightest stars, both of 2nd magnitude, are Sigma Sagittarii or Nunki about 3° above the Moon, and Epsilon or Kaus Australis, the southern star of the bow or bottom star of the spout, about 7° to the Moon's lower right. The Moon sets 40° south of west at 10:10 p.m.

The final public observing nights at the Michigan State University Observatory until next spring will be offered tonight and Saturday, from 9:00 p.m. until 11:00 p.m., sky conditions permitting.

Tonight with good 50mm binoculars or a telescope, you can locate Neptune, the most distant of our solar system's eight planets. At nightfall, find the constellation Capricornus in the south. Here's how: Its western end is a pair of stars Alpha and Beta, 2.4° apart (with Beta lower left of Alpha) and 14 to 16° upper left of the Moon tonight. You can also find them by drawing a line from Vega to Altair and nearly 25° beyond Altair, bending a little west of the extended line. Binoculars reveal both Alpha and Beta to be double stars. Alpha's components of about 3½ and 4th magnitude are wider apart and closer to equal and so more easily split than Beta's of mag. 3 and 6. Some 21-22° east (left) of Alpha and Beta is 2.8-mag. Delta Capricorni, tail of the Sea-goat and brightest star in this constellation. To confirm Delta, look for 3.7-mag. Gamma within 1.8° to its right and a little lower. Look 10° west (right) of Delta, for 4.1-mag. Theta Cap. Next, look 4° east (left) of Theta on a line toward Delta, to find 4.3-mag. Iota Cap. Neptune ends retrograde about 1.3° NW (upper right) of Iota tonight and moves very little for several weeks. Don't confuse 8th-mag. Neptune with the much brighter 5.3-mag. star 29 Capricorni 2.3° NW of Iota. Through a telescope magnifying 200-power, Neptune show a tiny bluish disk, contrasting in color with the distinctly reddish star 29 Cap 1.0° to the planet's northwest.

On Monday, we'll give directions to a much easier target for binoculars, 6th-magnitude Uranus. Don't forget to set your clocks back one hour tonight if you are changing to standard time. Daylight saving time in 2007 will be in effect from the 2nd Sunday in March (March 11) until the first Sunday in November (Nov. 4).

The public observing night at the Michigan State University Observatory from 9:00 p.m. until 11:00 p.m. tonight (if sky conditions permit) will provide a chance to observe these two outermost planets.

In the late afternoon and early evening, the Moon, near First Quarter, is 90°, or one-quarter of a circle, to the east of the Sun. The Sun is now in Virgo and about to cross into Libra, while the Moon is in Capricornus.

The star Arcturus today is nearly 33° due north of the Sun and is equally well seen at dawn and dusk. It is getting lower each day at dusk and higher each day at dawn. It's now quite easy to see low in WNW one hour after sunset, and low in ENE one hour before sunrise. On Monday an hour before sunup, Virgo's brightest star Spica is just rising 15° south of due east and rises 4 minutes earlier and climbs higher each morning. On what date will you first see it?

Here's a star-hop to the planet Uranus, for skywatchers with binoculars: After nightfall, when the Moon passes due south (7:43 p.m. EST in East Lansing), use binoculars to see the 3rd-mag. star Delta Capricorni, tail of the Sea-goat, about 2° to the Moon's upper left. First-magnitude Fomalhaut, mouth of the Southern Fish, is 21° to Moon's lower left. About 14° above Fomalhaut is 3.3-mag. Delta Aquarii, and another 8° above Delta is 3.8-mag. Lambda. Finally, look 0.8° SW (lower right) of Lambda for 6th-mag. Uranus. Compare the greenish color of Uranus to reddish Lambda and to 6.2-mag. yellow-orange star 78 Aquarii 0.6° to Lambda's NE (upper left). (Telescopes enhance the colors, and reveal Uranus's disk.) Uranus retrogrades, moving slowly WSW until Nov. 20, when it will be nearly 1.0° to Lambda's SW.

Fading Mercury is now 16° from the Sun and at its minimum distance of 3.2° SSW (lower left) of Jupiter, but it sets in very bright twilight from mid-northern latitudes. Mercury is now best from the equator and low southern latitudes. But even there Mercury is rapidly closing in on the Sun and will disappear within a couple of days. On Wednesday, Nov. 8, Mercury will transit the Sun's disk for nearly five hours, beginning at 2:12 p.m. EST (11:12 a.m. PST). At least some of the event will be visible from all of North America and Hawaii. For information on viewing the transit and on eye safety, visit http://sunearth.gsfc.nasa.gov/eclipse/OH/transit06.html and http://sunearth.gsfc.nasa.gov/eclipse/SEhelp/safety2.html

Please send any comments, suggestions, or questions to Shane Horvatin: horvati3@msu.edu