The Dudley Observatory

Skywatch Line for Friday, March 31, through Sunday, April 2
by Alan French

The Moon was new last Wednesday and is now moving toward first quarter. On Friday night you’ll see a pretty crescent Moon toward the west around 7:15 PM. You should be able to see the entire Moon, with the slender crescent brightly illuminated by the Sun, and the rest of the Moon faintly lit by the light of the nearly full Earth.

Sky watchers are in for a treat just after sunset Saturday night, April 1 (no fooling!). As the Sun sets the Moon will be among the stars of the Pleiades star cluster, also known as the Seven Sisters. The Moon’s eastward motion among the stars will move it across the stars of the Pleiades, hiding them from view. Any sort of optical aid – binoculars, spotting scope, or telescope - will reveal stars around the Moon. Watch for a while and you’ll see the edge of the Moon approaching a star. As it hovers at the edge, watch closely – the star will suddenly blink out and vanish from sight behind the Moon. The sudden disappearance shows the Moon has no atmosphere, and that the stars are so far away they appear as points of light.

Weather permitting the Albany Area Amateur Astronomers will host a public Star Party this coming weekend. At Star Parties a variety of telescopes are set up for your viewing pleasure, providing views of galaxies, star clusters, nebulae, and pretty double stars. Saturn is at its best right now, and will be a featured object at the beginning of the Star Party.

The Star Party is in Indian Meadows Park in Glenville, on Saturday night, April 1, beginning at 8:00 PM. Indian Meadows Park is off of Droms Road in East Glenville , and is marked by a large sign. After passing the park buildings, bear left at the fork in the road, and continue to a gravel parking lot on your left. The telescopes are set up beyond the gravel parking lot. Please park in the gravel lot and walk to the telescope area. If you are bringing a telescope, you may drive to the observing area, but try to arrive early.

There is no admission charge and all ages are welcome. You are welcome to stay as long or as briefly as you wish. Keep in mind that the temperature feels 20 to 30 degrees cooler when you are inactive under the night sky – so dress appropriately! It never hurts to have some extra layers of clothing in the car – some guests leave early because they get chilled. Star Parties are canceled if the skies are mostly cloudy.

Call Alan or Sue French at 374-8460 for more information or to verify a cancellation due to cloudy skies.

Skywatch Line for Monday, April 3
by Joe Slomka
The Sun sets tonight at 7:23 PM, Daylight Savings Time. Night falls at 9:02 PM. Dawn breaks at 4:55 AM, and ends with sunrise at 6:32.

At sunset, three objects pop into view. The six day old Moon blazes about four degrees above a dim red spot, the planet Mars. Mars is now traveling between the horns of Taurus and heading east. Saturn is the third object, high in the southeast, in the otherwise dim constellation of Cancer. Saturn remains close to the Beehive star cluster; both should be visible in a singular binocular view. Saturn creeps closer to "The Beehive" all month.

By nightfall, the Moon-Mars group shifts to western skies, while Cancer-Saturn occupies the center. The major constellation Orion starts setting, while Canis Major, with its brightest star Sirius, lies low in the South. Leo, the Lion, is now rising higher. Leo does not require much imagination to picture a lion; the backwards question mark makes a fine mane and neck, while the rectangle and triangle form the body and hindquarters.

Midnight finds Jupiter already well up and the constellation Bootes also high in the south-
East. The Moon and Mars are low in West, preparing to set between 1:30 and 2:00 AM. For those with a telescope, rural skies and looking for a challenge, Comet Schwassmann-Wachmann 3 occupies a dim area east of Arcturus. The comet promises to become brighter in the next two months.

Dawn finds Jupiter in the West, while Bootes and the comet are high overhead. Sunrise finds Jupiter preparing to set and Venus rising in the southeast.

Since the constellation Leo dominates tonight's sky, let's consider its brightest star: Regulus. Regulus is a sun-like star, burning hydrogen to make helium, but also different. It is about 350 times brighter but only about three and a half times as massive and larger. While our Sun takes 26 days to spin, Regulus spins every 16 hours. This is dangerously close to spinning itself apart! As a result, Regulus is oblate - flatter at the poles and bulging at the equator.

Clear Skies

This is the Dudley Observatory Skywatch Line for Tuesday, April 4th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 6:33 AM, and it set tonight at 7:24 PM. Sunrise tomorrow will be at 6:31 AM and Sunset will be at 7:25 PM.

The Moon is in a waxing crescent phase today, with the First Quarter Moon on Wednesday. Today it rose at 10:23 AM, and it set at 2:58 AM tomorrow morning. Look for the Moon tonight, just above the planet Mars, which is in the west about one and a half hours after Sunset. Tomorrow evening, the Moon will be near Pollux, in the constellation of Gemini, and on Thursday, the Moon will be near the planet Saturn.

The winter constellations of Orion the Hunter, Taurus the Bull, and the Seven Sisters are now getting very low in the west after darkness, and will soon be fading out of sight. In the meantime, the Spring constellations of Leo the Lion and Bootes, are rising higher in the east.

The planet Mars, looking like an orange-yellowish star, is above the horns of Taurus the Bull, and it is lower in the west than it was a month ago.

At the same time, the planet Saturn is high up in the west by the time darkness arrives. It is located in the Constellation of Cancer, near the famous cluster of stars known as the “Beehive”.

The Planet Jupiter rises around 9:00 PM, and is in good view by 11:00 PM. It is also visible in the west before Sunrise. Venus, the brightest object in the Solar System after the Sun and the Moon, is in the east before Sunrise.

Public Programs at the Suits-Bueche Planetarium at the Schenectady Museum, are on Saturdays and Sundays at 1, 2, and 3 P. M. The 1:00 program is “The Sky Above Mister Rogers Neighborhood”, a program for young people. At 2 P. M. is “Cowboy Astronomer”, and at 3 P. M. is a live narration of the Winter Sky. “Cowboy Astronomer” also plays Tuesday through Fridays at 2 PM.

Skywatch Line for April 5, 2006
by Bernard Forman

The Sun sets tonight at 7:25 PM. The Moon, in the constellation Gemini, the Twins, is at First Quarter.

The late sunset is due, of course, to daylight savings time, which started last Sunday. While most people appreciate having extra daylight hours after work or on weekends, many an amateur astronomer dislikes the practice, since it results in later observing sessions and, consequently, even less sleep. There are other accommodations to be made. If you use a planisphere, you must remember to subtract one hour when matching the date and time. The sky’s appearance can be disconcerting, with the Winter constellations setting more than an hour later compared to last week, and the Spring constellations being further to the east at the same hour. Of course, it helps to remember that the heavens have not changed, except, of course, for the slow, predictable changes due to the Earth’s revolving round the sun, and the Moon moving in its orbit. Rather, our perception has been changed through artificial tinkering with the way we keep time.

At 10:00 PM Orion still hasn’t set. Regulus and the Sickle portion of Leo are due south. Leo can also be found using the stars in the bowl of the Big Dipper. Both pairs of stars on either side of the bowl, pointing south, point in the general direction of Leo. The stars in the handle of the bowl readily point to Arcturus, in the constellation Bootes, the Herdsman. Once Arcturus is found the rest of Bootes, which is made up of stars considerably dimmer than Arcturus, can be made out. Many liken its outline to a kite or an ice cream cone.

Finally, between Arcturus in Bootes and Denebola in Leo, we find the faint constellation Coma Berenices, or Berenice’s Hair. To my mind, Coma Berenices has no recognizable shape. Coma Berenices is a relatively modern constellation, being formed from part of Leo by the Dutch cartographer Mercator in the middle of the sixteenth century. On a clear dark night, away from city lights, you can make out the Coma Star Cluster, which spans several degrees of the sky. Binoculars will show it to advantage.

Skywatch Line for Thursday April 6, 2006
by Bob Mulford

Yesterday, the moon was at first quarter phase. Although this phase of the Moon is called first quarter, exactly half of the Moon's visible surface was illuminated. The term "1st quarter" actually refers to the fact that one quarter of the lunar month has passed. Each day, the Moon completes part of its monthly journey around the Earth. Tonight, a very bright gibbous moon is high in the south-southwest at nightfall tonight. The Moon is said to be in a gibbous phase when it has passed first quarter and is more than half illuminated, but is not yet full.

The bright golden star-like object just below the moon tonight is the planet Saturn. Over the next few days, watch as the Moon moves a bit farther towards the east, to the left of Saturn, each day. This occurs because the Moon is moving along its orbit around the Earth. As the Moon orbits the Earth, it appears to move eastward in front of the stars. On Saturday evening, a fat, two-thirds full Moon will be seen just above the bright star Regulus in the constellation Leo the Lion. The lion is the king of the beasts and the name Regulus is Latin for "little king". It was given to the star by the 15th century polish astronomer Copernicus. However, Leo is an ancient constellation and Regulus has been associated with royalty by all the early mid-eastern civilizations. Leo is also one of the constellations of the zodiac. There is nothing magic about the Zodiac. These star patterns merely mark the path of the Sun, Moon, and planets in front of the stars.

If it is clear Saturday or Sunday morning, you might catch a glimpse of elusive Mercury just before Sunrise, a few degrees above the eastern horizon. Mercury is very bright and can still be seen as morning twilight is beginning and most of the stars have faded from view. Unfortunately, this month Mercury will not climb very high in the sky before daylight overtakes it. Early in June, there will be a much better opportunity to see Mercury in the evening sky, just after Sunset.

Sunset takes place at 7:31 PM; night falls at 9:12. Dawn breaks at 4:41 tomorrow morning, and ends with sunrise at 6:20.

As the sky darkens, three bright objects appear. The Moon is brightest and appears moderately high in the southeast. The Moon is twelve days old. Saturn is next brightest and lies due south and very high. This is the highest Saturn gets for many years. Mars appears as a tiny orange dot just beyond the tips of Taurus, the Bull. Mars, this month, drifts from between Taurus' horns to between the feet of Gemini.

By nightfall, all three have shifted into slightly better positions. Jupiter rises about 9:30, but midnight is the optimum time to see it; it outshines the dim constellation Libra, which resembles a diamond. While the observer needs a telescope to appreciate Saturn's rings, only binoculars are needed to see Jupiter's famous four moons.

The hour before sunrise sees Jupiter preparing to set, with Venus flashing low in the southeast. Strong binoculars or a telescope shows Venus over half lit. Mercury presents a challenge object. It is dimmer and much lower to Venus' left. This is Mercury's poorest appearance in northern skies and the observer considers himself lucky if he locates it. If he does, his telescope will see that Mercury is illuminated about the same as Venus' half.

Those living in rural areas with dark skies may try for two difficult objects. Just before Dawn, Comet Pojmanski appears between Cepheus, which resembles a house, and Cassiopeia, which is "W" shaped. Comet Schwassmann-Wachmann 3 is found near Arcturus, the main star in Bootes. Arcturus is easily found by following the arc of the Big Dipper's handle. Both are tenth magnitude and require some skill to locate. Comet Pojmanski is now leaving the inner Solar System for the dark, cold far regions. Comet Schwassman-Wachmann is, on the other hand, heading inward. It promises to be visible to the naked eye in mid May. The comet was discovered seventy years ago, and determined to return every five years.

This is the Dudley Observatory Skywatch Line for Tuesday, April 11th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 6:21 AM, and it set tonight at 7:32 PM. Sunrise tomorrow will be at 6:19 AM and Sunset will be at 7:33 PM.

The Moon is in a waxing gibbous phase today, with the Full Moon on Thursday. Today it rose at 5:46 PM, and it set at 5:49 AM tomorrow morning. Look for the Moon during the next few nights in the vicinity of the star Spica, in the constellation of Virgo. It will be near Jupiter on Saturday.

The winter constellations of Orion the Hunter, Taurus the Bull, and the Seven Sisters are now getting very low in the west after darkness, and are rapidly fading out of sight. In the meantime, the Spring constellations of Leo the Lion and Bootes, are rising higher in the east.

The planet Mars, looking like an orange-yellowish star, is above the horns of Taurus the Bull, and it is lower in the west than it was a month ago.

At the same time, the planet Saturn is high up in the west by the time darkness arrives. It is located in the Constellation of Cancer, near the famous cluster of stars known as the “Beehive”.

Tonight sunset is at 7:33 PM. The moon rises at 6:48 PM and sets tomorrow at 6:07 AM. Full moon occurs tomorrow so the moon will definitely interfere with our view of the nighttime sky.

Of the major, naked eye planets, Mercury and Venus are visible in the morning. Mercury, however, is very close to the horizon and will be exceedingly difficult to spot, lost in the sun’s glare. Venus is a bit easier to spot but it, too, will be near the horizon, rising less than two hours before dawn.

Returning to the evening sky, Mars is in the West at sunset. Look for Mars in the constellation Taurus, near the tips of the bull’s horns. Of course, Mars is well past opposition and, accordingly, a disappointing object in a telescope.

Saturn, near zero magnitude in the constellation Cancer, the Crab, is still quite prominent. Look for Saturn high up in the west southwest, about three degrees below the Beehive Cluster.

Finally, Jupiter, in the constellation Libra, rises in the southeast at 9:24 PM. Slightly dimmer than minus three magnitude, Jupiter will be unmistakable as the brightest object in the evening sky, except for the moon. Late in the evening, it will be possible to see, from west to east, Mars, Saturn, the moon and Jupiter, all at the same time. The line connecting them is the ecliptic, the apparent yearly path of the Sun on the celestial sphere due to the Earth’s orbital motion. The planets, and our moon, never stray far from this apparent path.

The nights around full moon, generally speaking, are the least desirable for astronomical pursuits. Even dedicated lunar observers prefer times when lunar features cast long shadows, bringing mountains, craters and other features into stark relief. However, even the casual observer can discern the contrasting patterns of the bright highlands and the dark maria. While most craters seem to disappear at full moon, several stand out only near full moon. Of particular interest are the systems of rays extending from certain craters, particularly the large crater Tycho.

If you have a simple lunar map handy, or even if you don’t, try viewing the moon, first, without optical aid. What features can you see? Next, try viewing the full moon with binoculars. At first, your eyes will be dazzled, as the moon is very bright. But after a while, you should even discern some craters.

Of course, when the moon is at first or third quarter, even the smallest telescope will give breathtaking views of our nearest neighbor. No other object in the nighttime sky is as easy to observe, or is as impressive, as the moon.

Skywatch line for Thursday, April 13, 2006
by Ray Bogucki

Tonight, the Moon is at its full phase. This means that the full Moon rises in the east just as the Sun is setting in the west. Earthly observers are facing the Moon with the Sun directly behind them so that the full face of the Moon is completely illuminated. The full Moon may be a boon for romantic song-writers and night travelers, but it is the bane of most astronomers. The bright light of the full Moon brightens the sky so that the faint galaxies and nebulas that are favorite targets for astronomers are essentially washed out in the moonlit sky. Indeed, many working observatories allow viewing nights for a day or two on either side of the full Moon when visitors can use the telescopes to view bright objects, such as planets, since there is not much else for the telescopes to do.

How bright is the full Moon? There are some interesting aspects to this question. For example, one might intuitively assume that the full Moon is twice as bright as the first or last quarter Moons which are 50% illuminated. In fact, the full Moon is about 10 times brighter than a quarter Moon, largely because the Sun's light is reflected to Earth at a 90 degree angle from the quarter Moon's surface and much intensity is lost in the process.

Actually, the Moon's surface has an average albedo or reflectivity of only about 7%, similar to the reflectivity of an asphalt road. If the Moon were as reflective as the bright planet, Venus, it would be 11 times brighter than it is, easily providing enough light to read a newspaper by. When we compare the full Moon to the Sun, we find that the Sun provides 450,000 times more light than the full Moon. If we could fill the entire night sky with full Moons, touching each other from horizon to zenith, we would still receive only 20% of the light of the single Sun.

Historically, the Moon, in its various phases, has played a critical part in the calendrical and religious traditions of humans. The native Americans in this area kept track of the seasons by giving a distinctive name to each recurring full Moon. Some of the better known names are the Harvest Moon in September and the Hunter's Moon in October. Tonight's full Moon was called the Pink Moon, with alternative designations as the Sprouting Grass Moon, the Egg Moon or the Fish Moon.

Following Jewish religious tradition, tonight's full Moon is the marker for the beginning of Passover. In western Christian tradition, Easter always falls on the Sunday following the first full Moon after the vernal equinox. It is thus a movable feast that can fall on any date between March 22 and April 25. Many Muslim holy days are determined by the first visual sighting of the new thin crescent Moon, usually within 24 hours after a particular New Moon.

This is the Skywatch Line for Monday, April 17.
by Joe Slomka

The Sun sets at 7:40 PM with night falling at 9:23. Dawn breaks at 4:26 tomorrow morning and ends with sunrise at 6:09.

As night falls, Mars and Saturn shine through the dusk. Mars is a small orange dot in Gemini, near Castor's foot. Saturn blazes high in the South. Both planets are quite close to star clusters. Saturn lies close to the famous "Beehive" cluster; the stars truly seem to swarm. Meanwhile, Mars lies quite close to M-35, another star cluster. An observer will probably see M-35 as a hazy cloud; a telescope will probably be necessary to see the cluster's full glory. M-35 is a group of about 300 stars located about 2000 light-years away. It is truly a spectacular object.

Jupiter rises shortly after nightfall. By midnight it is well placed for observation low in the South. Observers in rural areas may be able to train their telescopes on the constellation Bootes and see a remarkable sight. Comet Schwassmann-Wachmann is found between the head of Bootes and Corona Borealis.
However, the comet is in the process of breaking up. Over the past few weeks, observers have noted that the comet is breaking into several pieces. The cause of the breakup is most likely due to Jupiter's gravity. Whether the comet can survive a close approach to the Sun in June is a good question.

The Moon rises after midnight and ruins views of dim objects. Brilliant Venus is moderately high by 5:30 AM. A telescope-equipped observer will see the crescent of Venus accompanied by usually difficult Uranus within the medium power view.

An interesting fact is that spacecraft are now observing three of the brightest planets in our sky. The two rovers and two Mars orbiters continually study mars. The Cassini orbiter monitors Saturn. Now, the Venus Express has set up shop around that planet. All of these missions are available on the Web with stunning pictures and analysis broadcast at least weekly. The New Horizons spacecraft is now en route to Pluto, while more Mars missions are in various stages of completion.

Clear Skies
Joe Slomka

Skywatch Line for April 19, 2006
by Bernard Forman

The Sun sets tonight at 7:41 PM. The gibbous moon, almost sixty percent illuminated, does not rise until 2:20 AM Thursday morning in the constellation Sagittarius. Third quarter moon occurs tomorrow night.

With the winter constellation Orion, the Hunter, sinking in the west, we are reminded of the story where Orion was stung to death by a scorpion. Fittingly, Orion is placed in the sky so that he sets when Scorpius, the Scorpion, rises. Sure enough, by 11:00 PM tonight, the topmost stars of Scorpius are just peeking over the horizon in the southeast. Also visible further up we find returning summer constellations Hercules and Lyra. If conditions are good, we can follow the Milky Way hugging the horizon all the way from the winter constellations to Deneb, in Cygnus, just peeking over the horizon in the northeast.

But, truly, the night belongs to the constellations of spring, where we are looking, not along the galactic plane, but away from it. Spring is galaxy season, not because galaxies are predominantly distributed away from the plane of our own galaxy. Unlike nebulae, and open and globular clusters, galaxies are evenly distributed in the sky. But because the view is clearer away from the obscuring gas and dust, we see more galaxies when we look out away from the plane of our galaxy.

Of course, from our position slightly less than 43 degrees north latitude, we cannot observe most of the galaxies visible below the plane of our galaxy. Fortunately, however, the nearest major cluster of galaxies is in the northern sky, straddling the border between the constellations of Virgo and Coma Berenices.

The Virgo Cluster is located approximately forty-five million light years away and contains as many as three thousand galaxies. Dozens of cluster members are visible in modest size amateur telescopes. In fact, the view through a telescope can be rather confusing since nowhere else in the northern sky can an observer see so many galaxies at a time. Of course, even in rather impressive amateur telescopes, visually most galaxies appear gray and indistinct.

As we approach new moon, darker skies afford better opportunities to observe distant galaxies. If you attend a star party this spring, you are sure to see quite a few.

Skywatch line for Thursday, April 20, 2006
by Ray Bogucki

As the sky darkens into night these April evenings, the Milky Way, which marks the plane of our disk-like galaxy, is nowhere to be seen. The rotation of our planet has aligned the band of the Milky Way with our horizon, and its soft glow is lost in the horizon glow of nearby town and cities. While the brilliant collection of winter constellations is preparing to set in the west, the southern sky appears curiously dark and relatively sparsely sprinkled with stars. This reflects the fact that most of the stars in our galaxy reside in the spiral arms which form the galactic disk and will therefore appear in our sky not far from the Milky Way.

A happy exception to this general case is the fairly bright constellation, Leo the Lion, which rides high and lonesome in our southern sky. Leo is easily recognized by the sickle-shaped curve of stars open toward the west, also known as a backwards question mark. The curve was seen as forming the lion's mane. Just east of the sickle is a precise right triangle pointing east which forms the hind quarters of the Lion with the bright star, Denebola, at the tip of the tale.

The brightest star in the constellation, at the bottom of the sickle's handle, is first-magnitude Regulus, known since antiquity as a royal star which guards the heavens. At a distance of 77 light-years, and about 50 million years old, Regulus is an impressive young star about four times as large as the Sun and 140 times more luminous. Unlike our Sun's leisurely rotation period of one rotation every 26 days, Regulus rotates once in 16 hours so that the rotational speed at its equator is almost 700,000 miles per hours. This high rotational speed generates a large equatorial bulge which forms Regulus into a pumpkin shape. Regulus lies very close to the ecliptic so that the Sun passes within a degree of the star each year in late August. Regulus is also regularly visited by the planets and the Moon, which occasionally occults the star.

The modest star directly above Regulus, where the handle of the sickle joins the blade, is eta Leonis with a magnitude of only 3.5. But, while Regulus is impressive, eta Leonis is a hot, blue-white supergiant of truly heroic proportions. It is 14,000 times more luminous than the Sun and, if we equate the Sun to the size of a pea, Regulus would be about the size of a golf ball, and eta Leonis would be two or three times the diameter of a basketball. The reason that this brilliant giant appears so faint is that it shines from the staggering distance of 2130 light years. The light from eta Leonis that enters your eye tonight left the star's surface before Julius Caesar was born in Rome.

Next week's Skywatch line will continue the exploration of this fascinating constellation.

This is the Skywatch Line for Monday, April 24.
by Joe Slomka

The Sun sets tonight at 7:48PM, with night falling at 9:35. Dawn breaks at 4:11 AM, ending with sunrise at 5:58.

As the Sun sets, Mars and Saturn continue to rule the evening skies. Mars is a small red spot high in southwest, while Saturn is also high in the South. At nightfall, both objects lie within a binocular view of a star cluster. Mars is four degrees East of M35, which appears hazy in binoculars but grand in a telescope. Saturn is less than three degrees from the Beehive Cluster - a swarm of stars in your binoculars. Saturn is always a crowd favorite at star parties; but now is a special time to see Saturn. The Ringed Planet is now ninety degrees from the Sun. The sideways sunlight causes Saturn's shadow to fall on the ring system, giving the telescopic image an unusual three-dimensional aspect.

By midnight, Jupiter has arisen and lies low in the southeast. Jupiter is close to Alpha Librae, a double star in the constellation Libra. Jupiter's appearance in a telescope has changed markedly. A second Red Spot has appeared close to the more famous "Great Red Spot." Obviously, a new storm has arisen in Jupiter. Planetary astronomers are studying "Red Junior" for clues on Jupiter's weather systems. "Red Junior" can be seen an amateur telescopes. How long it will last or whether it will remain "red" is the subject of speculation.

Tuesday morning presents a beautiful sight. At about 5 AM, brilliant Venus blazes low in the southeastern dawn. If you have an unobstructed horizon, you may be able to spot a very thin crescent Moon. Binoculars may help spot the eight percent sliver to the Moon's lower left.

Below the obvious constellation Leo, the Lion, lies the dimmer constellation Hydra. This constellation begins with a triangular head and snakes toward the southeast. In fact, it is the longest constellation; it takes seven hours to fully rise. The constellation represents one of Hercules' trials - the many-headed snake.

Dudley Observatory Skywatch Line for Tuesday, April 25th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 5:59 AM, and it set tonight at 7:48 PM. Sunrise tomorrow will be at 5:57 AM and Sunset will be at 7:49 PM.

The Moon is in a waning crescent phase today, with the New Moon on Thursday. Today it rose at 4:47 AM, and it set at 5:28 PM. With the Moon rising before the Sun, the Moon can be seen during the day, just to the west of the Sun.

By 10:00 PM, the Belt of Orion, Taurus the Bull, and the Seven Sisters have dipped below the horizon. By 9:00 PM, Leo the Lion is due south, and almost overhead, and the Big Dipper is just about directly overhead.

The planet Mars, looking like an orange-yellowish star, is above the horns of Taurus the Bull, and it is lower in the west than it was a month ago.

At the same time, the planet Saturn is high up in the west by the time darkness arrives. It is located in the Constellation of Cancer, near the famous cluster of stars known as the “Beehive”.

The Planet Jupiter is low in the east by 10 PM, and is also visible low in the west before Sunrise. Venus, the brightest object in the Solar System after the Sun and the Moon, is in the east before Sunrise.

The Sun sets tonight at 7:49 PM preceded by the waning crescent moon, which sets at 6:46 PM. New moon occurs tomorrow.

By 11:00 PM tonight Mars, in Gemini, is sinking in the west, with Saturn higher up in the constellation Cancer, the Crab. Saturn is still a fine sight for amateur telescopes. Jupiter has already risen, at 8:21 PM in the constellation Libra, and is better placed for viewing later after it has risen above the horizon and the thickest part of earth’s atmosphere. Jupiter passes the meridian and, accordingly, is highest in the sky, at 1:25 AM Thursday morning, five minutes earlier than the previous morning.

In the morning sky, Venus rises at 4:21 AM on Thursday morning but is not favorably place as the Sun rises about one and a half hours later. Mercury is lost in the Sun’s glare and is, accordingly, not visible.

With the onset of spring, our view of the nighttime sky is away from the disk of our own galaxy. The band of the Milky Way hugs the northern horizon and is, generally, obscured. This affords us the opportunity to peer outside our own galaxy, generally free of the obscuring gas and dust within its spiral arms. Our attention is drawn to the myriad other galaxies, “island universes” which are the nighttime prey of the amateur astronomer on a balmy spring evening.

Imagine yourself at a star party during the spring. Avoid the temptation to look first at Saturn since it is so bright that it will spoil your night vision and make it more difficult to discern faint objects. As you go from one telescope to another, each aimed at a different galaxy or group of galaxies, what do you see? Most likely, galaxies described by the attending amateur as bright actually appear to be rather dim. You may discern, in the larger and brighter galaxies, a definite shape. Some are round, some oblong and some spindly. Under good conditions, with dry and steady air, only one or two galaxies will display any spiral structure. With practice and concentration, you will see more but galaxies, to the uninitiated, do not have the visual impact of, say, a bright nebula, or a fine open or globular cluster.

Viewing galaxies is, in many ways, a cerebral activity, requiring imagination in addition to observing skills. Each galaxy, which may appear as nothing more than a little smudge in the eyepiece, contains billions of stars and may, in other ways, resemble our own galaxy. Perhaps our own galaxy appears as nothing more than a gray smudge of light in a telescope being used in a galaxy far away.

Skywatch line for Thursday, April 27, 2006
by Ray Bogucki

At nightfall, the relatively bright constellation Leo, the Lion can be found high in the southern sky. A handy way to locate Leo is first to find the Big Dipper climbing high into the eastern sky. The two outermost stars in the bowl of the Dipper, the well-known "pointer stars" will lead you to Polaris, the "North Star", if you follow the line of the pointers to the left or north. If you follow the line of the pointers in the opposite direction, to the South, it leads directly to Leo with its characteristic shape of a sickle with a right triangle just east of the sickle.
Last Thursday's Skywatch line described the bright star, Regulus, at the base of the sickle and the much larger, but fainter star Eta Leonis just above Regulus where the sickle handle joins the blade. The next bright star along the curved blade is Gamma Leonis, also known as Algieba. This star is a second magnitude star similar in brightness to Denebola, the star in the lion's tail at the point of the triangle. While Denebola is a white star, the eye detects a color difference with Algieba which appears distinctly yellow or golden, which indicates that Algieba is cooler and probably older than Denebola. A small telescope provides a pleasant surprise - Algieba is actually a close double star, with a small separation of about 5 arc-seconds. The two stars are similar in brightness and golden color and are generally considered to form one of the finest close pairs in the sky. The two stars are gravitationally linked, revolving around their common center of mass with roughly a 619-year period. Fortunately, the pair is slowly separating in our line of sight so that it will, over time, become easier to split the pair with a small backyard telescope.
Another notable star in Leo is designated as R Leonis, located about 5 degrees west of Regulus. This is one of the brightest of the long-period giant red variable stars known as Mira Class stars With a roughly 312-day cycle, R Leonis varies from just visible to the naked eye at magnitude 5.5 to a hundred times fainter at magnitude 10. These pulsations can be followed with binoculars, or more easily with a small telescope. A star atlas will help in locating it. R Leonis is particularly known for its fiery red hue at all stages of its cycle. These giant red variable stars seem to be undergoing large scale expansions and contractions caused by periodic imbalances between gravity and fusion as they use up the last of their energy resources. R Leonis should reach its maximum brightness in June,when you might spot it without optical aid.

This is the Skywatch Line for Friday, April 28, through Sunday, April 30.
by Alan French

The Moon was new last Thursday afternoon, and will moving back into the early evening sky over the weekend. A very thin crescent will be a challenge to see on Friday night. On Saturday and Sunday nights, a beautiful crescent Moon will grace the evening sky just after sunset and the fall of darkness.

To see a very young thin crescent Moon on Friday night you'll need a very good view of the west-northwestern horizon, free of obstructions and clouds. The Sun sets at 7:53 PM and you'll want to look for the ghostly crescent around 8:45 PM. The Moon will be only five degrees above the west-northwestern horizon. (As a reference, remember that a fist held at arms length spans 10 degrees across the knuckles.) If you do find the Moon, you'll be seeing a Moon that is only 29 hours past new. Also, look for the Pleiades or Seven Sisters about six degrees to the upper left of the Moon.

The Moon will be higher and much easier to spot on Saturday and Sunday nights, and it should be a very pretty sight. When you spot the crescent Moon, note you can see the rest of the Moon glowing faintly within the crescent. This is called Earthshine, and it is simply the bright sunlight reflected off the Earth. If you were standing on the near side of the Moon over the weekend, you would see a nearly full Earth in the sky.

On Saturday night, look for the Moon around 9:00 PM when it will be almost 15 degrees above the west-northwestern horizon. Note that the Moon is now 8 degrees above and left of the Pleiades. As the sky darkens the Moon will sink toward the horizon, but you may find the Earthshine appears brighter against the dark sky. The Moon will set at 10:42 on Saturday.

At 9:00 PM on Sunday night, the Moon will stand 26 degrees above the horizon and the crescent will appear somewhat fatter. The Earthshine should be very obvious and pretty by about 10:00 PM when the sky is nice and dark. The Moon will set at 11:50 on Sunday.

During the coming week the Moon will move eastward among the stars and higher in the sky as it moves toward first quarter.