The Night Sky : This Week : October 12 – 19, 2010 !

The Sky This Week, 2010 October 12 – 19

An Ancient Story of the Season

Jupiter, 2010 OCT 11, 01:45 UT Imaged with the USNO’s 30.5-cm (12-inch) f/15 Clark/Saegmüller refractor

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The Moon skims along the southern horizon this week, passing through the setting summer constellations before climbing back towards the north through the fainter stars of autumn. First Quarter occurs on the 14th at 5:27 pm Eastern Daylight Time. Luna lies just above the teapot-shaped asterism formed by the brighter stars of Sagittarius, the Archer, on the evening of the 13th. From there she treads a lonely path until the night of the 19th, when she passes about six degrees north of bright Jupiter.

The middle of October is one of my favorite times of the year. The seasonal change is almost as dramatic as the one that takes place in the spring, but instead of awakening from a long winter’s slumber the Earth is preparing for the coming lean times. Right now it feels as if my neighborhood is under some sort of siege as the oak trees drop their seemingly endless supply of acorns, while farther north the colors of changing leaves splash a riot of color over the landscape. These changes can be found steeped in the sky lore of cultures around the world. One of my favorite sky stories comes from the Native Americans of my New England home and involves one of the most recognized star patterns in the sky. Every year during autumn the seven stars that form the “Big Dipper” asterism graze the northern horizon during the late night and early morning hours of mid-October. The Big Dipper is part of the larger constellation of Ursa Major, the Greater Bear, in our Greco-Roman sky myths. To the natives who lived in the Berkshire Mountains of western Massachusetts and Connecticut, the Dipper also represented a bear, or at least the stars of the Dipper’s “bowl” did. The three stars of the handle represented three hunters, who chased the bear around the sky all year until this time of the year, when they finally caught it and killed it. The flaming red color of the changing maple trees in their world were thought to be stained by the blood shed from the bear’s wounds. If you look closely at the star that forms the “bend” in the Dipper’s handle, you might see a faint star nestled next to the brighter one. This was the pot that the hunters would use to cook the slain bear!

The early evening still offers keen-eyed skywatchers a fleeting glimpse of the planet Mars. He is currently traversing the faint stars of Libra on his way toward a conjunction with his ruddy rival, the star Antares, in November. You’ll probably need binoculars to pick the red planet out in the deepening twilight of the west-southwest sky, where he sets an hour and 20 minutes after sunset.

Much easier to spot is giant Jupiter, whose bright glow may be seen low in the east shortly after sunset. As the sky darkens he climbs higher into the southeastern sky, and by the end of evening twilight he is well placed for telescopic viewing. He now culminates high in the south at around 11:30 pm, which allows for several hours of fascinating viewing through the telescope. Jupiter’s four large “Galilean” moons offer an endlessly shifting configuration from night to night, while his famous Great Red Spot offers an interesting and colorful target for patient observers who observe him at the right times. Good nights to look for the Spot this week are the evenings of the 15th and 17th at around 10:00 pm EDT.

The Night Sky : This Week : October 5 – 12, 2010 !

The Sky This Week, 2010 October 5 – 12

Triangles, Squares, Jupiter, and a Comet!

Jupiter, with the Great Red Spot and “Little Red” Imaged on 2010 OCT 3, 03:40 UT from Alexandria, Virginia, USA

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The Moon returns to the evening sky as a waxing crescent as the week ends. New Moon occurs on the 7th at 2:44 pm Eastern Daylight Time. Look for Luna’s fattening crescent in the southwestern sky shortly after sunset on the evening of the 9th. If you have a pair of binoculars, see if you can pick out the ruddy glow of the planet Mars about five degrees above the two-day crescent. Two nights later the Moon may be found about four degrees east of the ruddy star Antares, perched just above the southwest horizon as twilight ends.

You still have much of the week to enjoy the best of the autumnal sky before the Moon’s brightness begins to wash out the sky’s fainter objects. October has always been my favorite stargazing month, since the temperatures usually haven’t hit the freezing point yet and the summer’s best targets are still in view for the first couple of hours after dark. Evening astronomical twilight ends at around 8:15 pm, and at this time the stars of the Summer Triangle are directly overhead. The great star clouds of the Milky Way wend toward the southwest, and if you sweep the area between the Triangle and the horizon with binoculars or a small wide-field telescope you can catch many of the bright star clusters and nebulae that inhabit this stretch of the sky. By midnight another geometric figure, the “Great Square” of Pegasus straddles the meridian, with bright Jupiter parked just below. This area of the sky offers a “window” to distant external galaxies as we look south of the Milky Way’s plane. On clear nights from dark skies you can easily pick up the lozenge shape of misty light that betrays the Great Andromeda Galaxy in your binoculars, and if your surroundings are very dark you can easily see it with the naked eye. Draw an imaginary line from the lower right star in the Great Square through the upper left star to point yourself to our nearest large galactic neighbor. Larger telescopes reveal subtle detail in Andromeda’s delicate haze, and patient sweeping of the area around the square will show dozens of more distant galaxies to the sensitive eye.

High in the north at the midnight hour look for the “W”-shaped grouping of stars that portray Cassiopeia, one of the major figures in the Perseus-Andromeda myth. Binoculars and dark skies this week offer the possibility to see a fuzzy visitor to the inner solar system, Periodic Comet Hartley-2, which is making one of its closest approaches to Earth in its 6.46 year journey around the Sun. It will pass a mere 11 million miles from Earth on October 20th, and right now it is an easy target for binoculars and small telescopes. As the week opens it may be found below the left side of the “W” of Cassiopeia; as the week evolves it moves down toward the head of the wishbone-shaped constellation of Perseus. Look for a softly glowing greenish glow with a brighter center.

Jupiter is now the showpiece of the overnight hours. His bright glow has tricked many people into mistaking him for Venus, but the latter planet is now approaching solar conjunction and would never be found in this part of the sky at midnight. Old Jove has been rewarding owners of small to medium sized telescopes with wonderful views of his ever-changing cloud bands and shuttling moons. At a star party that I attended last weekend a young girl expressed delight at seeing the four Galilean moons in her rickety “department store” telescope. Her reaction at looking through several of the amateur telescopes set up nearby was even more enthusiastic. We’ll be able to continue enjoying Jupiter’s antics for the rest of the year, so keep an eye on him for constant changes.

The Night Sky : This Week : September 28 – October 5, 2010 !

The Sky This Week, 2010 September 28 – October 5

Planets going, planets coming, and autumn skies at their best.

Jupiter, cylindrical projection map of features Based on observations made 2010 SEP 18 – 22 Map produced with WinJUPOS 8.3.3 from webcam imagery.

 

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The Moon wanes in the morning sky this week, rising with the stars of the Great Winter Circle before wending her way toward the spring constellations by the week’s end. Last Quarter occurs on the 30th at 11:52 pm Eastern Daylight Time. On the morning of September 30th Luna stands high above the stars of the upraised “club” of Orion. Before dawn on the morning of October 2nd, look for her in the company of Castor and Pollux, the Twin Stars of Gemini.

The Moon’s disappearance from the evening sky means that it’s a great time to take advantage of prime fall observing weather. We still have summer’s bright star patterns and the magnificent star clouds of the Milky Way to enjoy in the early evening. Astronomical twilight now ends well before 8:30 pm, and as it fades the stars of the Summer Triangle are passing directly overhead. In the south and southwestern sky the densest star clouds of the Galaxy linger for binocular perusal, and you can trace the river of amorphous light overhead and down to the northeast horizon, panning the view for star clusters and bright knots of nebulosity. By 10:00 pm the fainter stars of autumn begin to invade the south and southeastern sky, while off to the east you’ll see one of the fall’s more distinctive star patterns climbing high. As the Summer Triangle passes west of the meridian, four second-magnitude stars rise to meet it. These stars form an asterism known as the “Great Square” and are part of the constellation of Pegasus, the flying horse of the Perseus and Andromeda myth. All of the characters of this celestial play are located in the northeastern sky at this hour, and as the night moves toward midnight Andromeda, Cassiopeia, Cepheus, and Perseus all climb higher to displace summer’s setting patterns. This part of the sky is a deep-sky observer’s dream, loaded with bright star clusters in the Milky Way and faint galaxies far beyond.

Early evening twilight still offers a chance to see the bright dazzle of Venus in the southwestern sky, but her time to shine in relative prominence is about to end in a big hurry. Look for her shortly after sunset a few degrees above the horizon. On a clear night she should be relatively easy to spot about 20 minutes after sunset, but you’ll only have about 20 minutes to find her before she slips too low into the horizon haze. The ruddy planet Mars finally catches up to her and passes by just over six degrees to the north on the evening of the 29th. You’ll definitely need binoculars to spot the red planet since he is over 100 times fainter than his brilliant companion.

Jupiter now dominates the evening and overnight hours, virtually unrivalled by any other object except the Moon. Old Jove is just a week past his closest opposition in nearly 40 years and stands out like a beacon in the star-poor reaches of the autumnal constellations. The giant planet is now the prime target of most backyard telescopes, and his ever-changing bright cloud belts and dark zones offer a different palate for viewing every night. If you tire of trying to eke out fine detail on the planet’s cream-colored disc, you can enjoy the antics of the four large moons discovered by Galileo in 1610. On the evening of October 1st, if you turn a modest telescope toward Jupiter at 8:00 pm EDT, you’ll see the moon Callisto passing just south of the planet’s disc, while the moon Io drags its shadow across the cloud tops. At 9:33 pm Io’s disc emerges from the planet’s limb, with the shadow following 17 minutes later. It seems as though there’s always something interesting going on out there!

 

The Night Sky : This Week : September 21 – 28, 2010 !

The Sky This Week, 2010 September 21 – 28

Autumnal Equinox and Harvest Moon

Jupiter, 2010 SEP 21, 03:32 UT Imaged with USNO’s historic 12-inch Clark/Saegmüller refractor

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The Moon begins the week big and bright, then starts to wane as she slowly makes her way into the morning sky as she wanes through the gibbous phases. Full Moon occurs on the 23rd at 5:17 am Eastern Daylight Time. This happens to be the Full Moon closest to the autumnal equinox, so it is almost universally known as the Harvest Moon. The reason for this particular appellation has to do with the curious geometry of Luna’s orbit for Northern Hemisphere observers at this time of year. If you’ve been following the Moon’s phases this month you’ve probably noticed how close to the southern horizon her path has been. This means that her orbital plane intersects the eastern horizon at a shallow angle. During most of the year her distance with respect to the horizon increases by 10 to 12 degrees each night, resulting in her rising about an hour later from one night to the next. At this time of year, though, Luna’s orbit intersects the horizon at a very shallow angle, so her nightly depression below the horizon is only a few degrees. This means that successive Moon rises around the time of Full Moon differ by 20 minutes to half an hour at our latitudes, which in the “old days” gave farmers a little extra light to work their fields to bring in the harvest. At high northern latitudes the Moon actually rises earlier on successive nights!

This year’s Harvest Moon takes place within hours of the autumnal equinox, which falls on the 22nd at 11:09 pm EDT. At that instant the center of the Sun’s disc will be located directly over the Equator just west of Papua New Guinea, passing from the northern hemisphere of the sky into the southern hemisphere. Since the Sun subtends a tangible disc, though, the actual time when we see exactly 12 hours between sunrise and sunset won’t occur until a few days after the equinox. Here in Washington that phenomenon occurs on the 26th. This is also the time of year when the change in length of daylight occurs at its most rapid rate. There is no mistaking that the days are getting shorter!

The evening twilight hours still find Venus and Mars chasing each other through the southwestern sky. Venus is still dazzlingly bright and can be easily spotted in the twilight glow within a few minutes of sunset. Mars, on the other hand, is some 100 times fainter than Venus and will probably require binoculars to see before he sets. The red planet may be found about seven degrees above and to the right of Venus.

Jupiter has just passed opposition, and now rises at sunset, sets at sunrise, and is visible in the sky all night long. If Old Jove appears particularly bright to your eyes this year there’s a good reason for that: he’s now closer to Earth than he’s been at any time since 1963. On the 20th at around 5:00 pm EDT he was a mere 367,540,544 miles (591,499, 169 kilometers) from Earth! His apparent disc is now about as large as it ever gets, so be sure to get a look at him through the telescope. Fortunately he will remain in fine form for viewing for the rest of the year, but we’ll have to wait until the fall of 2022 to see him this close to us again. As it happens, another planet reaches opposition at just about the same time as Jupiter. Distant Uranus is currently located less than a degree to the north of the giant planet, and may be seen as a faint star-like object with binoculars close to Jupiter. A small telescope will reveal Uranus’ tiny greenish-grey disc. Look for the nearly Full Moon six degrees above Jupiter on the night of the 23rd.

Early risers have the rest of this week to see the best morning appearance of fleet Mercury until the beginning of next year. The swiftly moving planet may be found due east in morning twilight about 12 degrees below the rising bright star Regulus in the constellation Leo. Mercury moves about a degree per day toward the horizon, but he is also growing brighter. Look for him with binoculars about half an hour before sunrise.

The Night Sky This Week : September 14 – 21, 2010 !

The Sky This Week, 2010 September 14 -21 Looking over the Moon, Jupiter at opposition The Moon Imaged 2009 NOV 22, 23:45 UT with a 50mm f/10 “Galileoscope” and a Canon PowerShot A95    The Moon brightens the evening sky this week as she wends her way through the southern constellations of the Zodiac. First Quarter occurs on the 15th at 1:50 am Eastern Daylight Time. She starts the week off to the east of the bright star Antares in the constellation of Scorpius, then drifts over the “Teapot” asterism of Sagittarius before entering the nearly empty sky of the autumnal constellations. By the end of the week she will approach Jupiter as the latter approaches opposition. It has been said many times that the Moon is “looked over, then overlooked” by amateur astronomers. Typically Luna is the first thing that owners of new telescopes focus their attention on, but after a few sessions spanning a few lunations they feel that they’ve seen all there is to see on the Moon’s desolate face and move on to other things. Those of us who enjoy the hunt for “faint fuzzies” or the intricate structure of the larger bright nebulae and star clusters often regard the Moon as the bane of our pursuit. However, our only natural satellite is also the one object that can be seen easily from virtually any location, no matter how blighted our sky is by local light pollution and smog. It doesn’t require much of a telescope to easily see Luna’s countless craters and other geological features, but the larger the telescope the more detail you’ll see. The Moon is the only object in the sky where we can spot features that come close to a scale that we humans can appreciate. The smallest crater pits visible in a typical amateur telescope are about a kilometer across, a distance most of us can walk in less than 10 minutes. In celebration of our closest neighbor in space, the evening of the 18th has been designated as the first annual International Observe the Moon Night (InOMN). This event is sponsored by “Astronomers Without Borders” in collaboration with NASA, whose Lunar Reconnaissance Orbiter (LRO) and Lunar CRater Observation and Sensing Satellite (LCROSS) projects met with great success last year. Here’s a chance to amaze your friends and neighbors with a glimpse of Luna through your telescope. Information on InOMN, including charts depicting Luna’s appearance on the 18th, may be found on the official website.  Moving outward from the relatively nearby frontier of the Moon, Earth’s next-closest neighbors in space are still vying for attention in the evening twilight sky. You should have no trouble spotting Venus shortly after sunset in the southwest. The dazzling planet reaches her greatest brilliancy in the evening sky this week, and maintains that brilliance for the next couple of weeks. She stands out well in the deepening twilight, and on exceptionally clear days may be glimpsed with the unaided eye some 40 degrees east of the Sun if you block Old Sol’s direct glare from your view. Much harder to pick out is Mars, which tags along with Venus about six degrees to the north and west. The red planet is about 100 times fainter than his brilliant rival, so you’ll probably need binoculars to pick him out of the horizon glow half an hour or so after sunset. As Venus settles toward the horizon, another bright object becomes prominent in the eastern sky. Giant Jupiter reaches opposition on the morning of the 21st, at which time he will be closer to us than at any time since 1951. His location among the faint stars of Pisces makes him stand out even more prominently, and many people have commented on the planet’s brightness to me lately. After gazing at the Moon, turn your telescope toward Old Jove. You’ll be rewarded for your effort! Early risers can catch a glimpse of fleet Mercury just before sunrise in the eastern sky. The planet reaches greatest elongation on the 19th, and should be an easy object to spot in the gathering twilight glow about half an hour before the Sun comes up.

USNO Master Clock Time Wed, 15 Sep 2010 08:02:34 UTC The Sky This Week The Sky This Week, 2010 September 14 -21 More…

The Night Sky : This Week : September 7 – 14, 2010 !

The Sky This Week, 2010 September 7 – 14

A weekend trip to Andromeda

Waiting for Andromeda Savage Farm, near Bluemont, VA September 2005

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The Moon spends the last two weeks of astronomical summer waxing in the evening sky.  New Moon occurs on the 8th at 6:30 am Eastern Daylight Time.  This is an important date in two of the world’s major religions.  For Jews it marks Rosh Hashanah, the traditional beginning of the new year.  For Muslims, the sighting of the first crescent Moon on the following evening marks the end of the fast of Ramadan and the celebration of Eid ul-Fitr.  Luna’s crescent waxes as she passes the planetary duo of Mars and Venus during twilight on the 10th and 11th.  On the evening of the 13th she will be just west of the ruddy star Antares in the constellation of Scorpius.  She ends the week crossing the dense heart of the Milky Way among the stars of Sagittarius.

I had the rare treat this past holiday weekend to not only benefit from the season’s first spate of wonderfully clear weather, but also an unfettered calendar for the evenings.  I took the opportunity to head off to a relatively dark site in Virginia’s northern Blue Ridge Mountains with my trusty 14.5-inch telescope to take in views of some summertime and rising autumnal favorite “deep sky” objects as well as the thrill of the chase in hunting down more distant celestial quarry.  For several hours I had an open meadow to myself, the crickets, katydids, and the stars and alternated between staring through the eyepiece at some far-off smudge of intergalactic light and kicking back in my observing chair and taking in the sight of the arching Milky Way with my slightly-corrected normal vision.  Such nights are as close to perfect as skywatching can get.  Moderate temperatures and transparent skies highlight the change of the seasons from the brighter star patterns and dense starfields of the summer to the relatively sparse constellations of fall.  On several occasions I pointed the big telescope at a random knot of naked-eye brightness in the Milky Way to be rewarded with an eyepiece full of a riot of distant stars too numerous to count.  However, the evening’s highlight came just before packing up the car for the drive back to civilization.  In the wee hours, high in the eastern sky, you’ll find a square-shaped asterism of second magnitude stars, part of the constellation of Pegasus.  Diverging from the northeastern corner of the square are two “chains” of stars, the lower one brighter than the upper, marking the constellation Andromeda.  Just north of the two stars that form the second ‘links” in the chains is an object that looks like a small detached part of the Milky Way, although the plane of the galaxy itself is several degrees distant.  This is the famous “Great Nebula” in Andromeda, first noted by the Persian astronomer al-Sufi in the 10th Century, and now known to be our closest intergalactic neighbor in space.  Some 400 billion stars comprise the Andromeda galaxy, and I spent about 20 minutes in rapt attention as I scanned the glow of those distant suns.  Simon Marius, the astronomer generally believed to be the first to view the object through a telescope around the year 1612, described the nature of its light as “that of a candle shining through [a ram’s] horn”.  I can think of no better description myself.  The light is airy and diffuse, stubbornly refusing to resolve into any kind of point source.  Subtle shadings and mottlings betray the presence of star clouds and dark rifts similar to those we see in our home galaxy, and the intensity of the light builds to a nearly stellar spot in the galaxy’s center.  Two satellite galaxies, both of which would be showpiece objects if they were isolated in the sky, accompany the great galaxy as it marches across the vault of night.  While the Andromeda galaxy is a wonderful treat for binoculars and small telescopes, it is simply magnificent in a large instrument at a dark site.

From the distant reaches of deep space to the more familiar confines of our solar system, the early evening twilight sky still offers views of the Earth’s two closest planetary companions as they race each other ahead of the advancing Sun.  Venus and Mars are now forging eastward away from the bright star Spica, which they both passed in the last two weeks.  This week the two worlds are briefly joined by the slender crescent Moon.  On the evening of the 10th Luna lies just south of Spica, with Mars and Venus to the left.  On the 11th she is east of Venus, with Mars just above and to the left of Spica.  This will be the last good opportunity to see the Moon and Venus together in the evening sky this year.

Giant Jupiter is inching closer to opposition on September 21st.  He now rises at around 8:00 pm, and his bright glow will command your attention shortly afterward.  Jupiter is about as bright as he can get since he is close to the perihelion point in his 12-year orbit around the Sun.  This also means that his disc is about as large as can be seen from Earth, almost 50 arcseconds across.  If you own a small or modest telescope, this will be the best year to seek fine detail on his surface markings since 1951!

The Night Sky : This Week : August 31 – September 7, 2010 !

The Sky This Week, 2010 August 31 – September 7

Meandering along the Milky Way, Planets at dusk & dawn.

Spica, the Moon, Mars, Venus, & Saturn Imaged over Hay Harbor, Fishers Island, NY, 2010 August 13, 20:45 EDT Canon PowerShot S2IS, 10 sec. @f/5, ISO 100	Jupiter, with Io & Europa Imaged from Fishers Island, NY on 2010 August 14, 06:05 UT

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The Moon wanes in the pre-dawn sky this week, with Last Quarter falling on September 1st at 1:22 pm Eastern Daylight Time. Luna begins the week in the company of the Pleiades star cluster on the mornings of the 31st and the 1st. She then wends her way as a waning crescent through the rising stars of the Great Winter Circle. On the morning of the 3rd she passes just south of the star cluster Messier 35 in Gemini. You should be able to spot the cluster in binoculars, but you should also have no trouble finding the familiar outline of Orion directly below the Moon as twilight begins to gather. From an ocean-facing horizon you should be able to see all the stars of the Great Winter Circle before twilight begins to wash out the view.

As the calendar steers us toward the last few weeks of astronomical summer the sky finds itself in a period of transition from summer’s bright stars to the relatively dim constellations of autumn. We are approaching the time of the year when the length of daylight is decreasing at its most rapid rate, so summer’s constellations seem to linger for awhile in the evening sky. Take advantage of this if you haven’t had a chance to go someplace well away from city lights to explore the billowy star clouds of the summer Milky Way. With evening astronomical twilight now ending at a decent hour of around 9:00 pm you have several hours of darkness to investigate this amorphous river of light and still turn in at a civilized time. Binoculars and my 3.1-inch rich-field telescope are my favorite tools for delving into the cosmic lagoons and backwaters of the galaxy, and from a dark location it is truly amazing at the number of stars and nebulae one can see with such modest optical aid. As the midnight hour approaches the southern sky becomes bereft of bright stars and Milky Way clouds, but if you turn your attention toward the northeast another arm of the Galaxy is swinging into view. After the star clouds of Sagittarius and the Summer Triangle have faded to the west, the area between Cassiopeia and Perseus is filled with yet more treasures for your enjoyment.

The evening twilight sky is still dominated by the bright glow of Venus, but the dazzling planet doesn’t stay visible past the end of evening twilight. Even though she reached her greatest elongation east of the Sun two weeks ago, her position on the Ecliptic keeps her low for northern hemisphere observers. This week she passes by the bright star Spica on the evenings of the 31st and 1st, gliding just over a degree south of the star. A few nights later the much dimmer planet Mars passes some 2 degrees north of Spica as he attempts to keep pace with his more dazzling planetary consort.

Late night skywatchers have been treated to the golden glow of Jupiter in the east as the giant planet rises a couple of hours after sunset. Old Jove is now just a few weeks from opposition, so he now rises on average about four minutes earlier each night. By the end of the week he will crest the horizon at around 8:00 pm, so those of us with early bedtimes can enjoy a good telescopic view of his streaked surface by 10:00 pm. He’s still missing his normally prominent South Equatorial Belt of dark clouds, so seasoned Jupiter observers are watching him like a hawk to see if there are any signs of the belt’s resurgence.

The Night Sky : This Week : August 24 – 31, 2010 !

The Sky This Week, 2010 August 24 – 31

The Joy of Vacation Stargazing

Spica, the Moon, Mars, Venus, & Saturn Imaged over Hay Harbor, Fishers Island, NY, 2010 August 13, 20:45 EDT Canon PowerShot S2IS, 10 sec. @f/5, ISO 100	Jupiter, with Io & Europa Imaged from Fishers Island, NY on 2010 August 14, 06:05 UT

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The Moon begins the week in her bright full phase, then wanes in the late night and early morning sky. Full Moon occurs on the 24th at 1:05 pm Eastern Daylight Time. August’s Full Moon is popularly called the Green Corn Moon, Grain Moon, or Sturgeon Moon. Luna spends most of the week drifting through the faint stars of the rising autumnal constellations. Her only encounter with a bright object occurs on the night of the 26th – 27th, when she rises with the bright glimmer of Jupiter and accompanies the giant planet through the morning hours. By the end of the week she begins to encounter the westernmost of winter’s bright stars as she closes in on Aldebaran and the Pleiades star cluster.

By the end of the week the light of the Moon is forestalled until around midnight. You’ve also probably noticed by now that the time of sunset is rapidly becoming earlier each night, so you will have several hours of darkness to enjoy the culmination of the summer constellations. Having just returned from a couple of weeks at a location with little light pollution and virtually no smog I can attest to the sublime beauty of the summer Milky Way and the bright stars that lie sprinkled through it. From the familiar “W” outline of Cassiopeia in the northeast, past the bright blue stars of the Summer Triangle overhead, down to the ruddy glow of Antares in the southwest, the galaxy holds a trove of wonders for skywatchers with and without optical aid. Some of my favorite moments from vacation were spent in a beach chair in the back yard of our house, picking out some of the more obscure asterisms and constellation patterns that inhabit this stretch of the sky. Occasional glances through my binoculars or 3.1-inch rich-field telescope kept me up until the wee hours, thoroughly entranced by the sights I’ve seen in many previous years from this spot. Clear skies on a dark island never get old! Summer stargazing is still at its best, and if you’ve got late summer vacation plans it is well worth it to stay up late a few nights while you’re away!

Over the past couple of weeks I hope you’ve had a chance to watch the interesting planetary dance in the southwestern sky during evening twilight. Bright Venus flirted with dimmer Saturn and Mars, and all were joined by a crescent Moon on the 13th. Saturn has been left behind by Venus and Mars as they continue to glide eastward against the stars. This week the two planets close in on the star Spica, which Venus will pass by the end of the week. On the evening of the 30th the planet will be just one degree south of the star. Mars will pass the star next week.

Bright Jupiter rises at around 9:00 pm EDT as the week begins. He gets a visit from the waning gibbous Moon on the evening of the 26th, and by the beginning of September he comes up at 8:30 pm. I had my first good look at Old Jove on vacation, and I can now verify that his telescopic appearance is very different that it was last year. His usually prominent South Equatorial Belt is now completely gone. This actually helps to bring out the view of the famous Great Red Spot, which over the past several years has almost blended in with the darker belt. It now stands out on its own and should be an easy sight in smaller telescopes. Jupiter will reach opposition in a few more weeks, so it promises to be an entertaining apparition this fall!

The Night Sky – This Week – August 11-24, 2010 !

The Sky This Week, 2010 August 11 – 24

 

Mars, Saturn, & Venus, 2010 August 8, 00:45 UT Imaged from Fishers Island, NY with a Canon PowerShot S2IS, 10 seconds @ f/3.2, ISO 50

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“The Sky This Week” is on summer vacation until August 24.  Here are some important dates and events to keep an eye on for the next couple of weeks.

First Quarter Moon: 2010 August 16  2:14 pm EDT      

Full “Sturgeon” Moon: 2010 August 24  1:05 pm EDT

The waxing crescent Moon is close to Venus, Mars, Saturn on the evening of August 13.  The three planets are low in the southwest during evening twilight.  Venus passes Mars between August 20 and 23.

The Perseid Meteor Shower peaks on the evening/night of August 12/13.  Look for up to 50 – 100 very swift meteors per hour from a dark sky location.  The Moon sets in Washington at 9:23 pm EDT, so it will not interfere with the shower.  Before midnight look for long trails from meteors striking the atmosphere at a shallow angle.  After midnight look for more meteors with shorter trails as Earth rotates into the meteoroid stream.  The “radiant” is located in the northeastern sky between the constellations of Perseus and Cassiopeia.  Meteors from the shower are visible for several days before and after the peak.

Jupiter rises at around 10:00 pm EDT early in the period.  By the end of August he rises an hour earlier.

The Night Sky This Week : July 27 – August 3, 2010 !

The Sky This Week, 2010 July 27 – August 3

Planetary “leapfrog”, and the joys of summer stargazing

Summer Stargazing at its best The Race, Fishers Island, NY, August 2006

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The Moon wanes in the late night and early morning sky this week, spending most of her time among the faint stars of the rising autumnal constellations.  Last Quarter occurs on August 3rd at 12:59 am Eastern Daylight Time.  Luna does pay a call on one bright object this week as she glides some six degrees north of giant Jupiter during the morning hours of the 31st.  By the week’s end the crescent Moon is closing in on the famous Pleiades star cluster.  

As Luna drifts into the morning sky, the stars of summer once again have an opportunity to shine.  Many of us take advantage of August as the time for a summer vacation, and going to the seashore or the mountains offers an opportunity to escape the haze and light pollution that surrounds our urban and suburban enclaves.  It’s also the time of year to see one of the most wonderful sights in all of Nature, the magnificent panorama of the summer Milky Way.  Our home Galaxy can be appreciated on many levels, with and without optical aid.  The wonderful sweep of its misty glimmer is often best appreciated by simply lying on your back in an open space such as a meadow or beach and simply looking up.  As your eyes become accustomed to the dark, subtle details in the Milky Way reveal themselves in the form of knots of nebulous light and patches of seeming emptiness.  In the hours after sunset and before sunrise the occasional satellite drifts through the field, a not-so-subtle reminder of our activity in space.  Hoist a pair of binoculars and the nebulous patches of the Galaxy become clouds of innumerable faint stars interspersed with knots of glowing gas and star clusters.  Point a telescope at these objects and watch them resolve into intricate tracings of delicate nebulosity or groupings of dozens to hundreds of stars.  From very dark locations the familiar outlines of many constellations become lost in an ocean of background stars and the sky itself seems to glow with a faint, suffused light.  Yes, summer stargazing is at its best as July turns to August.  Stay up late a few nights while you’re away!  

As you wait for the sky to darken in the hours after sunset, keep an eye on the southwestern sky, where three planets are participating in one of the best series of conjunctions for the year.  The objects in question are Venus, Mars, and Saturn, and they will spend the next couple of weeks playing a celestial version of “leapfrog” during the twilight hours.  As the week opens, both Venus and Mars lie to the west of Saturn.  By the end of July Mars overtakes and passes the more distant ringed planet, with closest approach between the duo falling on the evening of the 31st.  In the meantime, dazzling Venus is chasing down both objects, and by the end of the week you’ll see an attractive triangle in the southwest with Mars and Venus forming the base and Saturn the apex.  Looking ahead to August, Venus blows by Saturn on the 7th, then passes Mars on the 18th.    

All of this activity in the early evening sky sets the stage for the entrance of Jupiter, who rises just as Saturn and his companions set.  By the end of the week you should see Old Jove in the east at around 11:00 pm, and by midnight he should be high enough to train the telescope in his direction.  Jupiter will become an easier target as August passes, rising about four minutes earlier each night.  He’s still missing his prominent South Equatorial Belt of dark clouds, but this in turn helps to accentuate the famous Great Red Spot, which is the planet’s most famous feature.