Archive for August, 2013

The Sky This Week : August 27 thru September 3, 2013 !

The Sky This Week, 2013 August 27 – September 3
Tour our glorious Galaxy!
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Messier 11, the “Wild Duck” cluster

Imaged 2013 August 5 at Fishers Island, NY with a 3.1-inch (80mm) f/6
Antares Sentinel refractor and a Canon EOS Rebel T2i DSLR.

This cluster lies in front of one of the densest star-clouds of the Milky Way.

The dark patches are cold molecular clouds that obscure the light of
more distant stars behind them.

The cluster gets its popular name from its description by the 19th
Century British amateur astronomer Admiral William H. Smyth, who
described it in his 1844 “Bedford Catalog” as “resembling a flock
of wild ducks in flight.”

The Moon wanes in the morning sky this week, greeting early risers as she courses through the stars of early winter. Last Quarter occurs on the 28th at 5:35 am Eastern daylight Time. It’s a busy week for Luna as she starts her travels between the bright star Aldebaran and the Pleiades star cluster on the morning of the 28th. She then encounters bright Jupiter on the morning of the 31st. The next morning finds her located between the bright stars Castor and Pollux in Gemini and Procyon, lead star of Canis Minor, the Lesser Dog. Labor Day morning finds her six degrees south of ruddy Mars in the gathering morning twilight.

The Moon’s absence over the coming holiday weekend means that many of us will be visiting the beach or the mountains for a final summer weekend. If this is the case for you take some time, weather permitting, to spend an evening under the summer stars. If you didn’t catch the splendor of the summer Milky Way earlier in the season you’ve still got time to enjoy it now. The rippling star clouds of our home galaxy split the evening sky from northeast to southwest by the end of evening twilight, and you’ll have several hours to explore its many treasures with binoculars or a small telescope. On my recent vacation I had several clear, moonless nights to re-acquaint myself with the sky’s largest “deep-sky” feature, exploring it with binoculars, a 3-inch “rich-field” telescope, and my 9.25-inch aperture Schmidt-Cassegrain instrument. The view through each instrument had its own special rewards. In binoculars the fuzzy band of the galaxy begins to break up into waves of stars overlying a misty background. Here and there bright knots appeared where star clusters or bright gaseous nebulae beckoned for a closer look. The small scope showed these in the context of the deeper clouds of background stars, which begin to resolve into innumerable points of light. Finally, the big telescope resolved the clusters into hundreds of stars and revealed delicate structure in the wisps of gas and dust in the nebulae. If I had to choose one object that gives great views under each condition it would be Messier 11, a star cluster located about 20 degrees southwest of the bright star Altair. In binoculars M11 is a bright hazy patch of light set on one side of a chevron-shaped asterism. In the rich-field telescope it resolves into a tight clump of stars set against the background of a dense patch of the Milky Way known as the Scutum Star Cloud. Finally, in the big scope it resolves into hundreds of densely-packed stars that seem to “follow” a single bright reddish star across a background of thousands of fainter ones. You can easily get lost in the vastness of space when you spend some quality time under the Milky Way’s glow.

If you’re out before the end of twilight waiting for the Milky Way to appear, Venus and Saturn are there to entertain you. Venus shines brightly in the hour after sunset in the southwest. If you have binoculars you can watch her progress from night to night as she travels eastward along the ecliptic. By the end of the week she will be closing in on the bright star Spica. Venus will pass the bright star next week as she draws a bead on Saturn.

Saturn is now losing his cosmic footrace with the Sun and is now getting difficult to see against a dark sky. You should be able to sight him about half an hour after sunset, but if you want to try to catch a last good glimpse of him through the telescope you’ll have to observe him in twilight conditions. By the time the sky is fully dark he will be wallowing in turbulent air above the southwest horizon.

Jupiter is making headway toward the evening sky, but your best view of him will still be just before dawn. The giant planet should be very easy to find among the stars of Gemini, where he’ll spend the rest of the upcoming apparition. He will be placed very favorably for northern hemisphere observers this year, high on the ecliptic when he reaches opposition in January.

Ruddy Mars is also best seen just before dawn. This week the red planet drifts eastward through the dim constellation of Cancer, the Crab. If you have binoculars, watch him close in on the scattered group of stars known as the “Beehive”. He’ll cross the cluster next week as he continues his eastward march against the stars.

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The Sky This Week : July 23 thru August 20, 2013 !

The Sky This Week, 2013 July 23 – August 20
Things to see on summer vacation
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The rising Full Sturgeon Moon
Imaged from Fishers Island, NY, 2008 August 17

“The Sky This Week” will be taking a brief hiatus for a few weeks of summer vacation. There may be updates if I can find a reliable Internet connection while away.

The Moon wanes in the morning sky this week, closing out the month of July drifting through the rising autumnal constellations. Last Quarter occurs on the 29th at 1:43 pm Eastern Daylight Time. Luna begins August as a waning crescent, passing just over two degrees north of the bright star Aldebaran before dawn on the 1st. On the mornings of the 3rd and 4th you’ll find her playing “tag” with the bright planet Jupiter in the gathering morning twilight; on the latter morning look for dim ruddy Mars about five degrees to the north of the very thin crescent. New Moon occurs on August 6th at 5:51 pm EDT. Look for the waxing crescent near bright Venus in the evening twilight of the 9th. On the 12th she may be found just southwest of golden Saturn. First Quarter will fall on August 14th at 6:56 am EDT, with Full Moon occurring on the 20th at 9:45 pm EDT. August’s Full Moon is often called the Sturgeon Moon or the Green Corn Moon. It marks the traditional beginning of harvest time for many agrarian cultures, and will be followed in a month by the Harvest Moon.

Hopefully many of you will enjoy a summer getaway to the countryside or the shore, and hopefully these places are well away from city lights. The place where I go is mercifully unlit by local street lights and is far enough away from large cities to afford a spectacular view of the summer sky. If the weather is good and the mosquitoes can be held in check I plan to spend as much time under the summer Milky Way as possible, observing old favorite “deep-sky” objects and tracking down ones I’ve never seen before. No matter if I’m using my binoculars, my 3-inch wide-field refractor, or my 9.25-inch “big eye,” there should be plenty to keep me busy until the wee hours. The summer sky offers an amazing assortment of star clusters, glowing gaseous nebulae, colorful double stars, distant galaxies, and enigmatic “dark nebulae” for your enjoyment. In particular, the latter are in many ways the most fascinating. You’ll see these dark patches along the length of the Milky Way from a good dark site, and examination with binoculars or small telescopes will reveal that these clouds are vast aggregates of dark material that absorb the light of the more distant star clouds. The American astronomer Edward Emerson Barnard first cataloged these objects in the early 20th Century, finding well over 100 in the summer sky alone. The ancient Inca, who had the advantage of very dark skies and high altitudes, made up much of their sky-lore around these dark voids! Try to see if you can spot some of them over the next few weeks.

The highlight of every summer is the annual Perseid meteor shower, which generally peaks around August 12th to 13th. This year there will be almost ideal observing circumstances, with the Moon setting before midnight on the optimal dates. The shower’s radiant point in the sky rises in the northeast shortly before midnight and climbs higher as the morning hours progress. Located near the famous “Double Cluster” in the constellation Perseus, the radiant is part of the sky from which the meteors seem to originate as the Earth plows through the dusty stream of meteoroids sputtered from the surface of Comet 109P/Swift-Tuttle. Under ideal conditions a single observer may see up to 100 shooting stars per hour, but those ideal conditions don’t favor us this year. However, it would not be unusual to see rates of 50 to 60 per hour on the nights of the 12th and 13th. The Perseids are best enjoyed with the naked eye; they are very swift, usually quite bright, and often leave a persistent smoke train for several seconds after flashing through the sky. The best way to observe them is on a blanket or a lawn chair with a view of the wide-open sky. Point your feet to the northeast, lie back, and watch the show from about 1:00 am until dawn.

You’ll have a chance over the next few weeks to see all five of the naked-eye planets known to the ancients. They will congregate in the early evening and pre-dawn skies, so you can catch a few winks (except when the Perseids are active!) between your planetary viewing times.

Venus glimmers brightly in the western sky and comes into view almost immediately after the Sun sets. She gradually sets a bit later each night with respect to the Sun even though she sets earlier on successive nights by almanac tabulation. By the end of August she sets at the end of evening twilight, but until then she will be best seen while the sky still sports the sunset glow. She ends July fleeing from a close encounter with the bright star Regulus. During August she presses eastward along the ecliptic with Saturn in her sights.

Saturn is still visible in the evening sky, but he’s becoming increasingly difficult to see in steady air through the telescope. He is gradually plodding eastward among the stars of Virgo and shares the southwestern sky with that constellation’s brightest star, Spica. You can use Spica to gauge the quality of the atmospheric “seeing” before you point your telescope at the ringed planet; if the star is “twinkling” vigorously you’re probably not going to get a decent view. However, if the star looks very steady, Saturn should be a glorious sight.

Both Jupiter and Mars now rise before the beginning of morning twilight, but your best views of them will probably be had about an hour before sunrise. You should have no trouble spotting Jupiter as August opens, and he’ll climb higher in the east-northeast with each passing morning. Below and to the left of Jupiter you should be able to spot the dimmer red glimmer of Mars. As July winds down and August opens you should also be able to catch a glimpse of elusive Mercury, which reaches greatest elongation west of the Sun on July 30th. Mercury will be slightly brighter than Mars but a bit closer to the horizon. You should be able to keep him in view through August’s first week; he’ll then get lost in the solar glare.

I hope that most of you will have a chance to get out and do some serious viewing. It’s one of my favorite summer activities, and if I see something really special I’ll be sure to share it with you over the next several weeks.