To the reader:
The Skywatcher's Diary for November 2001 has been prepared by David Batch, Abrams Planetarium. Credit to Abrams Planetarium, Department of Physics and Astronomy at Michigan State University, and mention of our Sky Calendar, would be appreciated.
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 the web directly at URL:
http://www.pa.msu.edu/abrams/diary.html
Current and back issues of the Skywatcher's Diary are available in our archives at:
ftp://www.pa.msu.edu/pub/swd/
Skywatcher's Diary: November 2001
The Moon officially reached Full phase this morning at 41 minutes past midnight for those of us in the Eastern Time Zone. Farther west the event occurred on the previous day, October 31st. The next Full Moon happens on the last day of this month, producing two Full Moons in November.
Tomorrow morning, 45 minutes before sunrise, look low in the ESE for Venus and Mercury, less than a degree apart. Venus is the brighter of the two objects. Notice the bright start Spica, part of the constellation of Virgo, four degrees to the lower right of the planetary pair.
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Jupiter currently rises about 4 hours after sunset. It sits among the stars of Gemini, the Twins. Once Jupiter has cleared the treetops in the ENE, look for the bright Gemini stars Pollux and Castor, one perched atop the other, 10 degrees (a fist width) to the left of the planet. Jupiter begins retrograde today. Its apparent motion against the background stars will be westward for the next 4 months. If the night is particularly clear, you may like to drag out your telescope to take a close look at Jupiter because the shadows of two of the planet's moons, Io and Europa, will cross the planet's disk at the same time. The shadow show begins at 1:20 a.m. EST (tomorrow morning) and lasts until 3:11 a.m.
Saturn rises about 2 hours after sunset, and the Moon follows close behind. Watch for it to appear 2 degrees (4 moon diameters) to the lower left of the planet, low in the ENE. Earlier in the day the Moon passed in front of Saturn, hiding it from view. The occultation was visible from Europe, Russia, and a few other spots in the Eastern Hemisphere. We will have our chance later this month (November 30) and again in late December when much of the U.S. is correctly aligned to witness the Moon occult Saturn.
Continue watching Mercury and Venus every morning you are able. This is Mercury's best morning appearance of the year, and with Venus so close by, the pairing is a rare spectacle. For the next several days, the two planets are dropping, relative to the background stars, but at nearly the same rate, so the planetary duo seems to hang together low in the ESE 45 minutes before sunrise. By the 8th, Mercury begins pulling away from Venus and disappears into morning twilight around mid month. The bright star Spica is 4 degrees (half a fist) to the right of the planets tomorrow morning but quickly drifts upward and away as the days pass.
Jupiter and the Moon make a pretty sight as they rise, about 4 hours after sunset. The pair will continue to attract attention all through the night. They begin the evening 2 degrees (4 moon diameters) apart, with the Moon above Jupiter low in the ENE. As the hours drift by, the Earth's rotation carries the two higher toward the south. During the night the Moon's orbit also carries it back toward the east at the slower rate of one moon diameter per hour. Consequently, the Moon passes to within a degree of Jupiter around 1:30 a.m. EST. By dawn the pair appears more than two-thirds of the way up in the SW, with the Moon again about 2 degrees above the planet. A casual observer would assume the Moon remained stationary relative to the planet all night long.
Your last chance to see the 4 planets at once in the morning sky is fast approaching. Look 45 minutes before sunrise. Begin with Mercury and Venus close together just above the ESE horizon. Venus is the brightest point of light in the sky, although the approaching dawn will diminish its apparent luminosity. Move next to Jupiter, easy to spot as the brightest "star" high in the SW. Saturn completes the quartet, not quite halfway up in the west. The next opportunity to see 4 planets in one view occurs in mid January when Jupiter, Saturn, Mars, and Mercury stretch across the early evening sky.
This morning before sunrise the Moon is in line with Pollux and Castor, the Gemini Twins. Pollux is 9 degrees (a fist width) to Luna's upper right. Bright Jupiter is 15 degrees to the right. Tomorrow morning the Moon passes Last Quarter phase at 7:21 a.m. EST. As you gaze at the Last Quarter Moon you look in the direction the Earth travels in space as it orbits the sun. Tomorrow morning you are also looking at the boundary between the constellations Cancer, the Crab, and Leo, the Lion. The Moon passes into Leo about an hour after reaching First Quarter.
The Moon rises tonight around 1 a.m., technically tomorrow morning. The bright star 4 degrees (half a fist) to the Moon's lower right is Regulus, heart of Leo. By dawn tomorrow the pair has risen to two-thirds of the way up in the SE. The following morning (the 10th) the Moon slips to 16 degrees (a fist and a half) to the lower left of Regulus. The lion's tail, a 2nd-magnitude star called Denebola, can then be glimpsed 10 degrees to the Moon's left.
With the interesting morning action involving four of the five "naked-eye" planets, it is easy to forget about Mars, the lone early evening planet. A respectable magnitude zero, the orange dot easily dominates the southern sky which now contains the faint zodiac constellation Capricornus. Mars shares that constellation with two additional planets, both faint outer giants. Neptune is 3 degrees to Mars' right and Uranus is 11 degrees to the upper left. Later this month Mars acts as a pointer for Uranus when it passes less than a degree under the planet. Stay tuned.
At the end of dusk, 5 stars of 1st magnitude or brighter are visible. Three are easy to spot. They are the familiar stars of the Summer Triangle -- Vega, Deneb, and Altair, now visible high in the west. What are the other two? Capella should also be easy to find, as it comes up in the NE. Don't confuse Capella with Saturn. The planet rises later in the ENE. The remaining star is probably the least well known of the 1st-magnitude group. Look for Fomalhaut (foam«-all-ought) low in the SSE. It is in an utterly forgettable constellation, Piscis Austrinus, the Southern Fish, that never rises much above the treetops in mid northern latitudes.
Winter solstice occurs today. No, you haven't really lost a month and a half of prime holiday shopping. Today's solstice takes place on Mars. The Red Planet's north pole is now tipped farthest away from the sun. The severity of winter on Mars is determined by more than just the pole tilt. In contrast to Earth, Mars' orbit is quite elongated, so the distance of the sun during a Martian winter can vary greatly from year to year. This time the sun is relatively close, and the harshness of this year's Martian winter will be softened. The southern hemisphere's summer will, however, be enhanced.
This morning the Moon is a crescent, three days before New. During dawn it hangs in the ESE 10 degrees (a fist width) above Spica, the brightest star in Virgo, the Maiden. Tomorrow morning the Moon drops to 8 degrees to the lower left of Spica and 8 degrees above Venus. It is the last time to easily observe the Moon before New. Mercury is 2 degrees to the lower left of Venus. If you enjoy a challenge, try to find the Moon the following morning (Wednesday the 14th). Mercury and Venus can point the way. Look 40 minutes before sunrise very low on the horizon, just 3 degrees to the lower left of Mercury. Binoculars are helpful.
The winter constellations announce the coming of the cold season. Best known of the lot is Orion, which now rises 4 hours after sunset. Jupiter also comes up about that same time. It and Saturn are perched among the stars of the winter constellations of Gemini and Taurus, respectively. Sirius, the brightest nighttime star, rises about 5 1/2 hours after the sun. Watch it come up in the ESE. If you catch Sirius when it is low to the horizon, look for the star's prismatic twinkling, when it flashes all the colors of the spectrum.
When will you last see Mercury in the morning sky this month? The final sighting will come in the next several days. Look 40 minutes before sunrise just above the ESE horizon. Timing is critical. Too early and the planet won't be high enough to see, too late and the sky will be too bright. Use brighter Venus as a guide. Mercury sits 3.7 degrees below and slightly to the left of Venus. You will need binoculars, but once you spot the planet try to see it without optical aid.
New Moon occurs this morning at 1:40 a.m. EST. Ramadan, the Islamic month of fasting, begins with the first sighting of the crescent Moon after New Moon. For Muslims in the continental U.S., that sighting will occur tomorrow evening, rather than tonight. The Islamic calendar is lunar based, so each month commences with the young crescent Moon. Because this moon phase can only be seen for a short time after sunset, the new month always starts around sundown. Ramadan will end with the first sighting after the New Moon of December 14.
The thin crescent Moon will be relatively easy to spot this evening, provided you pay attention to timing and have an unobstructed southwestern horizon. The ideal time to look is 45 minutes after sunset, although you can begin trying 15 minutes earlier. At that moment the Moon will lie 12 degrees to the north (right) of SW and 3 degrees above the horizon. Bring along binoculars to help in initially picking out the Moon from the bright background twilight.
The Leonid meteor shower peaks tomorrow morning before dawn. Historically, the Leonids have produced some spectacular displays. Although predictions are inexact, it appears that the U.S. could be in for an impressive show this year, perhaps one meteor every few seconds. The peak will be brief -- an hour or less -- centered around 5 a.m. EST. Interfering moonlight is absent this year. Observe anytime after midnight but make certain to include the time around 5 a.m. Dare we think a once-in-a-lifetime event?
In 1966 observers in the central and western U.S. reported a Leonid meteor display that reached over 100,000 per hour. That works out to tens of meteors per second! While we don't expect this morning's showing to reach that level, it could well be impressive. Try to observe from a dark location where the sky is open, if possible. The meteors will seem to radiate from Leo but appear in all parts of the sky, so the wider your field of view the better. Equip yourself with a sleeping bag and a hot beverage for warmth, and a lounge chair for comfort.
The Moon makes an interesting telescopic target while at its crescent phase. The sunrise terminator -- the left (east) side of the crescent -- shows craters in surprising detail. Even binoculars provide a pleasing glimpse, particularly if you can mount them on a tripod or other rigid platform. Tonight see if you can spot the large dark oval known as Mare Crisium, the Sea of Crises. It is located a little above center and halfway between the terminator and the limb (right edge of the Moon). The "sea" is actually a huge crater whose floor has been filled with lava, now solid rock.
Tonight the Moon is 4 degrees (8 moon diameters) below Neptune. Don't expect to see this 8th-magnitude planet without a telescope and a detailed finder chart, however. Tomorrow night the Moon stands 3 degrees below Mars. Uranus is also in that vicinity, 4 1/2 degrees directly above the Moon. The three bodies form an almost equal-sided triangle. Next week Mars will help point the way to Uranus as it slides under the faint planet, passing less than a degree from Uranus. Start now using binoculars to familiarize yourself with the starfield around Mars.
Have you ever seen Mars in daylight? With the Moon's help tonight, you should be able to spot it before the sun sets. Use binoculars. Find the Moon a third of the way up in the SSE shortly before sundown. Look 3 degrees (6 moon diameters) above and slightly to the right for a "star." How soon after sunset will you be able to see Mars with just your naked eyes? Plan to keep looking 45 minutes or an hour after the sun goes down.
The First Quarter Moon occurs at 6:21 p.m. EST, so the terminator (day-night line) exactly cuts the Moon in half at that moment. Observe the terminator as close to the instant of First Quarter as you can, then again throughout the evening, and notice the change. Mars is 13 degrees (a fist width) to the right of the Moon. Fomalhaut, a 1st-magnitude star in the constellation of the Southern Fish, is the solitary bright star 16 degrees to the Moon's lower left.
To obtain a star map showing this and other sky events, send a self-addressed, stamped envelope to Sky Calendar, Abrams Planetarium, Michigan State University, East Lansing, MI 48824.
As the seasons change, the length of day goes from a maximum to minimum and back again. At the equinoxes the rate of change is fastest, quick enough to be noticeable by even a casual observer. Near the solstices the rate of change levels off and the status quo seems to prevail for months. Today, a month from the winter solstice, the length of day is only a half hour longer and night only a half hour shorter than what they will be at the official start of winter. A month beyond the solstice the lengths will again differ only by half an hour. The small change in daylight over such a long period adds to the perceived monotony of winter.
Mars passes near Uranus over the next several nights, providing a good opportunity to locate the faint planet. After dark, point your binoculars at Mars, the bright "star" one-third of the way up in the SSW. Position the binoculars so that Mars is located near the right edge of the field of view. On the left side, and slightly higher, look for the 2.8-magnitude star Delta Capricorni. Tonight it is about 4 degrees to the east of 0.4-magnitude Mars. Between Delta and Mars, and slightly lower, is 3.7-magnitude Gamma. Uranus, magnitude 5.8, is 1.5 degrees to the upper left of Mars. Uranus, Mars, and Gamma make an almost equilateral triangle. Watch for the next several nights.
Tonight Mars has moved nearly directly below Uranus, 1 degree away. Mars is 1.5 degrees from Gamma (lower left) and 3 degrees from Delta. Tomorrow night Mars is closest to Uranus, 0.8 degrees to the lower left of the faint planet. Mars is in line with Gamma and Uranus, slightly closer to Uranus. Continue following the movement of Mars as it pulls away from Uranus. The Red Planet moves 0.7 degrees each night. By the 30th it sits 1.4 degrees above Delta.
Now that you are in practice at finding faint objects with binoculars, here's another challenge: Vesta. The asteroid, at magnitude 6.5, is the brightest of any minor planet this year. It is in the vicinity of the stars of the V-shaped face of Taurus, the Bull. Vesta is 1.5 degrees to the lower right of Gamma Tauri, the point of the "V." To improve your chance of locating Vesta, wait until late evening so that Taurus is high in the sky. A detailed finder chart is also necessary. Such a chart, rotated 180 degrees as seen through a telescope, can be found at http://www.rasnz.org.nz/MinorP/Vesta.htm.
Saturn now rises during evening twilight and sits 10 degrees (a fist width) up in the ENE at the end of dusk. Jupiter follows the Ringed Planet by a little more than two hours, so both are nicely visible by mid evening. Saturn is currently retrograding within the constellation of Taurus. Aldebaran, the bright eye of the bull, appears 4 degrees to the planet's right, along with the Hyades, the V-shaped group of stars that mark the face of Taurus. The attractive Pleiades star cluster is 14 degrees above Saturn. Use binoculars to get the full impact of this cluster's beauty.
Take a look at the Moon tonight. Would you say that it is Full? Look carefully. Notice the eastern side is ever so slightly lopsided. The Moon will not be Full until November 30th. It then becomes the second Full Moon of this month for everyone in the Eastern Time Zone. The second Full Moon is commonly referred to as a "blue moon." This meaning of the term is a relatively recent aberration, however. Before 1946, "blue moon" was taken to mean the third full moon that occurred within a season that contained four full moons -- a more complex definition, to be sure. For details on the convoluted blue moon story see:
http://www.skypub.com/sights/moonplanets/9905bluemoon.html
Today the sun crosses the boundary into the constellation Ophiuchus (Off-ee-you«-kus). Never heard of that pattern, you say? It is part of the zodiac, as defined by astronomers, although not one of the classical twelve. The sun spends more time among the stars of this constellation than it does in Scorpius, the pattern immediately to its west. So in some sense Ophiuchus deserves to be part of the zodiac at least as much as the Scorpion. Ophiuchus, the Serpent Charmer, contains no 1st-magnitude stars but occupies a large area of sky. It is a constellation worth becoming familiar with. Now, unfortunately, is not the right time to the see the pattern, since the sun obscures it.
Tonight, for everywhere in the eastern and southern U.S., the Full Moon will occult Saturn. Shortly after sunset, as the Moon rises, Saturn appears a degree (2 moon diameters) to its left. As the pair climbs the eastern sky, the Moon's orbital motion draws it in front of the Ringed Planet and blocks our view for a time. Because the leading edge of the Moon is bright, Saturn's disappearance is more easily observed through a telescope. For exact disappearance and reappearance times for major cities, see http://www.lunar-occultations.com/iota/1201sat.htm.
(Times for Detroit: disappearance 7:47 p.m., reappearance 8:35 p.m.)
If you miss this event you have another chance. Saturn is occulted again in late December.
Please send any comments, suggestions, or questions to
Thomas G. Ferguson:
fergus52@msu.edu
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