Hollywood meets Orion

You might call it the Hollywood of the night sky. The Orion Nebula (top), located in the Hunter's Sword, is where all the fresh-faced stars hang out. Threading this cloud of cosmic gas and dust like tiny lights on a Christmas tree, more than 2000 new stars shine and shimmer. The brightest four form a compact group called the Trapezium, a mulitiple star at the heart of the nebula. The stars that comprise this little trapezoid-shaped group are 15-40 times more massive than the sun and so hot, they make the nebula fluoresce brightly enough to be seen with the naked eye.


The photograph shows Orion's Belt (top) and down below it, the Orion Nebula. The drawing (right) was made using 10x50 binoculars. Photo, drawing: Bob King

The next clear night, look to the south to find the familiar "three stars in a row" of Orion's Belt. One outstretched, gloved finger below the leftmost Belt star, you'll spy two or maybe three fainter stars in a vertical row. Does one of them look a little fuzzier than the others? That's the Orion Nebula, located some 1350 light years away. What you're seeing is the bright, unresolved Trapezium, blended with the soft glow of radiating gases around it.


This sketch gives you an idea of what the Orion Nebula looks like through a moderate-sized telescope (15" reflector) at a low magnification of 64x. On the darkest nights, the inner part of the nebula around the Trapezium (four stars) glows pale green, while the outer "tendrils" are a subtle pink. The nebula opens to the south (top) because my telescope reverses the image compared to a naked eye view. Sketch: Bob King

With binoculars, you should be able pick out two stellar spots embedded in a milky glow that fades to the south. If you look "around" the spot using instead of staring directly at it, you'll be able to discern the nebula's umbrella-like shape. A telescope under a dark sky shows a spectacular blossoming flower of nebulosity, tinged faintly with green and red. It's a treasure amateur astronomers return to night after night in spite of withering winter chill.

The Orion Nebula is 24 light years across -- almost five times the distance to the nearest star beyond the sun, Alpha Centauri -- and appears twice the diameter of the full moon in our night sky. It's a massive nearby region of intense star formation composed of hydrogen gas and fine dust spewed by earlier generations of stars. Within its cloudy confines, gas and dust collapse under the influence of gravity into new stars.

Nebulas like Orion are the Milky Way galaxy's recycling engines, churning out new generations of stars from the flotsam and jetsam of the old. Our sun was likely born in a nebula, since dispersed, more than four billion years ago. Stars in the Orion Nebula are very young. Astronomers estimate the Trapezium stars were "born" only 300,000 years ago, the same time that Homo erectus, a predecessor to our own species, was first learning to use fire.

Two photos of the inner part of the Orion Nebula. The left one was taken in regular, visible light while the right one was made in dust-busting infrared light, and shows a multitude of stars around the Trapezium group. Credit: NASA/ESA

Telescopes that can take pictures in infrared (heat) light, are able to penetrate the shrouds of glowing gas to reveal a very rich cluster of stars buried deep within the Orion Nebula. Newborn stars are taking shape this very day, and will in future until the gas and dust are used up. Millions of years from now, our descendants will look up and see a spectacular star cluster twinkling in place of the nebula.

Nature transforms all by simply letting things take their course.

For space station watchers, we're winding up the current cycle with the following passes. The station will first appear in the western sky and move toward the southeast over several minutes.
*Tonight Jan. 31 at 6:37 p.m. One of the brightest passes of them all. This one will cross nearly overhead.
*Sun., Feb. 1 at 5:29 p.m. and again at 7:05 p.m. Twilight sky on the first one but a good pass so you still might catch it.
*Mon., Feb. 2 at 5:57 p.m. Excellent high pass in the southwest.
*Tues., Feb. 3 at 6:25 p.m. Not as bright as previous ones. Look two fists high in the southwest.
*Thurs., Feb. 5 at 5:46 p.m. Last pass of this cycle. A tougher one -- low in the southwest during twilight.

(Topmost photo credit: Hubble Space Telescope - NASA/ESA)

Posted by: rking@duluthnews.com on 1/31/2009 at 12:30 PM | Comments (2) | Permalink

Venus, moon and clouds, oh my

Did you catch the moon and Venus last night? Clear but cold here in Duluth. I wandered around downtown near the end of my shift to see if I could align a triple conjunction between the pair and a city landmark. Tony Mitchell was out too, and shares his photo with us today.

The moon, a thicker crescent Friday night, will once again accompany Venus. This map shows the view during late twilight looking west. Created with Stellarium.

In case you were stuck inside, the moon will be near Venus again tonight. It's also not far from the Square of Pegasus, one of fall's most prominent constellations, now headed westward during the early evening hours. In honor of the celestial Square, I thought you'd enjoy a photo Andrew Kirk of Bishop, California sent me this week. He calls it a "rectilinear lenticular". It's a squarish-shaped lenticular cloud he saw over the Sierra Nevada Mountains.

The moon Thursday from the Holiday Inn First Street
entrance in downtown Duluth. Details: 135mm lens, f/2.8, 1/30" exposure at ISO 800. Photo: Bob King

Very pretty shot of the moon and Venus taken by Duluth's Tony Mitchell. Details: 1 sec exposure, 8 mm lens at f/4.5, and ISO 200.

This photo, submitted by Bill Eyler of Juda, Wis., easily shows Venus (upper left) at 4 o'clock Thursday afternoon. "I could see Venus very well with naked eye," said Eyler. "Today I saw it at noon using the moon as a guide."

Andrew Kirk's cool, square lenticular cloud. The lighting and color create a dreamy effect.

Iridescent clouds made a brief appearance just before sunset Thursday. The intense colors were caused by the scattering of light by microscopic droplets in the clouds. Photo: Bob King

Tomorrow we'll update the next round of space station passes and pay a visit to the nearest star forming region to Earth.

Posted by: rking@duluthnews.com on 1/30/2009 at 2:53 PM | Comments (0) | Permalink

How to keep a skywatching journal

Several excerpts from my astronomy journal written at the time of Comet Hale-Bopp (left), and Comet Shoemaker-Levy 9's crash into Jupiter (right). A journal is a great way to record what touches you in the night sky. Photo: Bob King

The crescent moon joins Venus tonight for a splendid pairing of the two brightest objects in the nighttime sky. Next, we throw in two passes of the International Space Station across the northern sky at 5:41 p.m. and again at 7:16 p.m. Finally, those hankering for a real challenge can take on the toolbag that got away from the Shuttle astronaut last year. Tonight it makes one of its brighter passes over our region beginning at 6:49 p.m.

The crescent moon and Venus will ornament the sky tonight (Jan. 29) during twilight. This map is drawn for 6 o'clock and shows a view to the southwest. Created with Stellarium.

The toolbag is only as bright as the faintest stars most of us can see with our naked eye, so it will require binoculars. I've seen it once and can tell you it moves much faster than the space station. Give yourself time to adjust to the dark, then point your binoculars in the optimal spot just to the left of the Little Dipper, and wait for it to cross your field of view. There goes thousands of dollars of tools -- up in space!

The lost toolbag will rise up out of the northwestern sky this evening (Jan. 29) and quickly move toward the Little Dipper. Your best bet for seeing this "mini" satellite is to point your binoculars a little more than one outstretched fist to the left of the North Star and wait for it to pass through the view. Or you could point to Alpha in the constellation Cepheus, which is midway between Deneb and the North Star. Created using Stellarium.

One of the pleasures of skywatching is keeping a journal of what you see. I started my first diary when I was 13. It included a potpourri of everything in my young life. It's fun to look through it now and enjoy salient moments like the description of the sweaty palms I experienced holding hands for the first time.

These days I keep an astronomy journal where I record my brushes with frostbitten fingers instead. Everything goes in there -- the weather, temperature, joys of discovery, night sounds, failed attempts to find faint thingies, chance meetings with passing strangers on snow machines and sketches.

I use an artist sketchbook with blank pages so it's easy to make a drawing without ruled lines getting in the way. My instruments are pencil, eraser and fingertip. Many deep sky objects are fuzzy blobs which can be rendered realistically by smudging a penciled outline with your index finger.

A journal gives one a certain discipline about thinking and seeing, helping me to express thoughts and feelings I have about the night. Writing also sharpens one's power of observation so the next time you go out, you'll see more there than you saw the first time. No artist by any stretch, I still find it fun to try my hand at recreating the look and feel of a moon-planet lineup or recording the weekly changes in Jupiter's cloud bands.

You can write as much or as little as you like, or add drawings and photos. The key is to let it out and not worry too much about grammar and punctuation.

Those who keep journals know what I mean. If you've never started one, tonight's series of events might just be what you need to give it a try.

Posted by: rking@duluthnews.com on 1/29/2009 at 12:34 PM | Comments (0) | Permalink

Striking a balance

This photo was taken while waiting for the sled dog mushers to arrive at a checkpoint in Beaver Bay, Minn. The lights at the site illuminated the birch trees which contrasted well with the night sky. Orion's Belt is at upper left. Details: 16mm lens at f/2.8, 30-second time exposure at ISO 800. Photos: Bob King

As long as you have a tripod handy, there's always time for sky photography. While on the trail of our regional sled dog marathon this past weekend, there were several good opportunities for astronomy-related pictures during my down time.

While I've never driven off the road into a ditch in pursuit of a photo, you don't want to be around me when an opportunity presents itself. My driving becomes erratic and I've been known to park the car in the middle of a highway ... briefly. One friend of mine drove off the road watching a northern lights display.

It's just so hard to pass up a great photo, yet most things happen unplanned and don't last long. I've jumped out of a car for many a wonderful scene only to see the action wrap up just as I sling the camera around my neck. Like a toad sitting patiently for hours until it snatches the unwary fly, you have to be ready to snap up the possibilities. Advance planning and anticipation help, but my underlying assumption is shoot the photo now or miss it. I did miss a few during the race: a wolf that wandered down to the highway and then turned back up the trail (I did a U-turn asap but too late), a grand sunrise in cold steam fog over Lake Superior (never found an opening without trees in the way), and a time exposure of sled dogs pulling sled and musher under the stars (didn't think of it till it was too late).

Gladys Peterson, who works with a ham radio club that monitors the progress of the mushers during the race, exhales a 'breath corona' as she warms up by a fire Monday morning near Tofte, Minn. The temperature was 16 below. Diffraction, caused by the microscopic water droplets in her breath, created a partial corona the same way a corona forms around the moon (left). The colors are even in the same order -- blue inside and reddish-orange outside.

I ran into a woman from Silver Bay, a small city along Lake Superior's North Shore, and she told me about a sunrise she saw but never photographed because she'd forgotten her camera. While I may be talking out of both sides of my mouth, let me just say it's OK she forgot. We sometimes rely too often on the camera and don't inhale the experience itself. Can we freeze a moment and really get around to enjoying it later? Somehow you have to find a balance between the need to record and the simple pleasure of the experience itself. There can be room for both.

Paul Boese, 18th century Dutch botanist, put it well over 200 years ago when he said:
"We come into this world head first and go out feet first; in between, it is all a matter of balance." 

The early morning sun reflects off the windows of a
resort in Tofte, Minn. which reflect again off the ice
of Lake Superior.

Posted by: rking@duluthnews.com on 1/28/2009 at 12:54 PM | Comments (2) | Permalink

Star candy for binoculars

The sun is partially eclipsed by the moon as it sets Monday, January 26 at Manila's bay in the Philippines. Credit: AP Photo/ Aaron Favila.

The moon passed directly between the sun and Earth yesterday and treated skywatchers across southern Asia and Australia to a solar eclipse. The thin crescent moon returns to our sky tonight welcome as a baby's first smile. To see it, look well below Venus in the southwest a half hour after sunset. One of our staff photographers here at the Duluth News Tribune and his wife are expecting their first child today or tomorrow. While I'm not superstitious, it feels right to come into this world under a young moon.

The delicate crescent moon is visible Tuesday evening in the southwestern sky shortly after sunset. This map is drawn for 5:30 p.m. As the sky darkens, you'll see the entire outline of the moon, which is lit by light reflected from the Earth called Earthshine. Created with Stellarium.

The space station continues its graceful arcs across Northland evening skies. Below you'll find the times to watch. All passes begin low in the northwestern sky, cross the north in the vicinity of the two Dippers, and fade away in the northeast. Look for a bright, moving star.

* Tuesday Jan. 27 beginning at 6:20 p.m.
* Weds., Jan. 28 " " 6:48 p.m.
* Thurs., Jan. 29 " " 5:41 p.m. In twilight, but it should still be visible.
* Thurs., Jan. 29 " " 7:16 p.m. A second pass the same night -- lower and shorter. 
* Fri., Jan. 30 " " 6:09 p.m.
* Sat., Jan. 31" " 6:37 p.m. and crossing nearly overhead. Brightest pass of the week!

On Thursday the 29th, the toolbag that slipped out of the hands of one of the Shuttle astronauts will make a good pass too. I'll have a map that day to help you find it in binoculars.

This map is drawn for around 7 o'clock in the evening as you look halfway up in the eastern sky. To find the star cluster M35, locate bright Betelgeuse at the top of Orion. M35 is one "Orion-length" straight up and above the left side of Orion. You can also draw an imaginary line (blue line shown) between the two stars equidistant from the cluster. Point your binoculars smack in the middle between them and a bit off to the left to find M35. Created with Stellarium.

Last night, after covering our annual John Beargrease Sled Dog Marathon, I took a walk under the stars to unwind. It was fun to stop now and again and check out the sights in binoculars. Poking around in Gemini the Twins, I paused at one of winter's brightest star clusters called M35. It's located in the "toes" of the constellation. From my semi-rural location, M35 was faintly visible with the naked eye as a fuzzlet of light.

While this isn't a very good photo, it does give you a pretty fair idea of how M35 looks in binoculars. The three stars connected by the blue lines are the same three tucked under the cluster in the map above. Details: 135mm lens at f/2.8, ISO 1600, 10-second time exposure. Photo: Bob King

Since I normally look at this cluster through the telescope, I was pleasantly surprised by how much character it showed in 10x50 binoculars. I could easily distinguish about a dozen stars within a sparkly cloud the size of the full moon (1/2 degree). Through a modest telescope, you'll see some 200 stars packed into a roughly circular outline 2800 light years from Earth. For reference, the Seven Sisters cluster (Pleiades) is about 400 light years away, while the V-shaped Hyades is only 151 light years.

We peer deeply into one of our Milky Way Galaxy's spiral arms when we spy M35 in binoculars.

M35 (left) and its dimmer "neighbor" NGC 2158 in a time-exposure photograph. Credit: 2MASS Sky Survey.

If you have a telescope you can go deeper yet. Just a bit southwest of M35 and almost touching, you might just catch a glimpse of another cloudy ball of stars. Called NGC 2158, this cluster is almost 16,000 light years away, five times as distant as M35. Although it appears to partner with M35, in reality it hints at the enormous depths of space that are to be found above our heads from our own front yards.

Posted by: rking@duluthnews.com on 1/27/2009 at 1:19 PM | Comments (5) | Permalink

Shadowed by Venus

Venus on Sunday night beckons from a clear, twilit sky. January is high season for Venus shadow hunting. The best time to look is between 6:30 and 7 p.m. around the end of twilight. Photos: Bob King

A couple weeks ago we talked about seeing your shadow by Venus light. Jim Schaff of Hermantown gave it a whirl and recently sent me this: "Last night I went out to see if I could see my shadow by Venus's light. I was able to see my arm shadow, but it was faint and indistinct. Perhaps it was because I was casting the shadow on a snowbank. Perhaps I was not far enough from town. I went out a little past Twig. But I could see it."

For those not familiar with Twig, it's a tiny berg, famed for its baked goods, a half-hour's drive north of Duluth. After reading Jim's e-mail, I hoped for an opportunity on a weekend night when I could get out early and try to see my Venus shadow. One big plus of minus zero weather is a bounty of clear nights, so on Saturday I took my camera and set it up at a lonely locale far from the maddening light of the city. After my eyes adjusted to the darkness, I could see the shadow of one of the tripod legs faintly. My photograph showed it too, but the experience didn't satisfy.

The next day it hit me. For maximum contrast, I should photograph the shadow of the camera projected onto a white posterboard. Sunday night I huddled in the cold dark again and lined up my subjects in a row -- posterboard, camera and Venus. Voila! The camera's shadow stood out clearly on the board.

Left: The shadow of my camera on a piece of white posterboard taken with the sun at my back. Right: The camera's shadow again but this time with Venus at my back. The Venus photo looks gritty because of the long time exposure in low light (80 seconds, ISO 3200, f/2.8 with a 35mm lens.) The bump on top of the camera in the right photo is the shadow of a device that helps me focus the camera at night. Notice how much sharper the Venus shadow appears.

Earlier in the day I'd done the same with the sun. Take a look at the two shadows in the photo. The sunlit one has fuzzy edges because the sun is a sizeable disk and acts like a thousand point sources. Venus is a singular point source of light and casts a much sharper-edged shadow. Can you see the difference? For more in-depth information on shadows, please visit this website.

You might also notice that Venus' shadow is much less dark than the sun's. That's because during the 80-second time exposure, light pollution from the city lit up the cardboard enough to reduce contrast.

I tried Jim's "arm manoever" in front of the posterboard and discovered that if you hold your arm a foot or so directly out from the board, the shadow becomes incredibly obvious. Much better than when cast on uneven ground. Give it a try yourself and you'll see what I mean.

Posted by: rking@duluthnews.com on 1/26/2009 at 4:50 PM | Comments (3) | Permalink

The ring bearer returns

You can use the Big Dipper to guide you to Regulus and from there to Saturn. This map shows the sky as you look east around 10 p.m. in late January.  If you go out later, Saturn will be even higher and easier to see. Created with Stellarium.

Saturn watchers can rejoice this January. The planet is now one of the actors on the evening sky's stage. Since losing Jupiter and Mercury earlier this month, we've had only Venus to light the way. No complaints about Venus, but the outer planets like Saturn, Mars and Jupiter have more to offer the telescopic observer like rings, moons, polar caps and changing weather.

While walking the icy roads the other night, I noticed that Saturn clears the trees in my neighborhood around 10 o'clock. It occupies a vacant area of sky below the outline of Leo the Lion. To find it, start with the Bowl of the Big Dipper in the northeast. Reach your arm out to the sky and make a ball with your fist. Regulus (REG-you-less), Leo's brightest star, is three fists to the right and below the Bowl. If you like, you can linger a while here, using Regulus to find the famous "Backwards Question Mark" asterism that forms the Lion's Head. Saturn is two fists below Regulus and a tad brighter. See that triangle of stars above the planet? That's Leo's tail. The brighter star at the far end of the triangle is Denebola (Den-EB-oh-la), which means "tail of the lion" in Arabic.

The last time Saturn's rings were edge-on from our perspective on Earth was in 1996. These photos, taken by the Hubble Space Telescope, show them barely visible (top), and slightly tilted.The dots are moons of the planet. Titan is the biggest in the top image. Although the rings are extemely wide -- 185,000 miles across -- they're less than a half-mile thick. Credit: HST/NASA

In an earlier blog, I talked about Saturn's rings. Their inclination or tip is very shallow this year. Presently, the planet looks like a butterscotch-colored orb with a toothpick stuck through it. The rings will open up just a little in the coming months before we see them completely edge-on later this summer. I shouldn't say "see", because when we view the rings exactly along the edge, they're so thin, they disappear in all but the very largest telescopes. Small telescope users will notice that Saturn is closely accompanied by what appears to be a moderately bright star. This is its largest moon Titan, which circles the planet every 16 days.

The full beauty of the rings is revealed in this stunning image taken by the Cassini spacecraft, currently in orbit around the planet. Credit: Cassini/NASA

Like two planets on a teeter-totter, as Venus goes down, Saturn comes up. Tonight Saturn rises at 8:50 p.m. while Venus sets at 9:13. Together the two light the way through the length of these bitter cold nights.

Posted by: rking@duluthnews.com on 1/25/2009 at 12:10 PM | Comments (4) | Permalink

Comets and almonds

Comet Lulin is a little gray-blue spot in this photo made this morning. Details: 70mm lens at f/2.8, 13-second time exposure at ISO 1600. Photos: Bob King

Clear skies last night but a long day at work and lashing subzero winds kept a roof between me and the stars. I applaud Tony (see yesterday's Comments) for his stand against the cold while exploring Cygnus. Instead I got up just before 6 this morning to check on Comet Lulin. With the start of dawn literally 15 minutes away, I had reason to be hopeful no matter what the temperature. Through 10x50 binoculars the comet was a soft fuzz. The view in the telescope was much better despite the turbulent air that made the stars billow and boil. Lulin was a bright blob about 1/4 the size of the moon with a dense, milky center.

If you tried to spot the comet and didn't succeed this morning, not to worry. Lulin will be brighter, higher and more conveniently placed for viewing in about three weeks.


Cyanogen gas makes Comet Lulin glow blue-green in this photo made with a 200mm telephoto lens Saturday morning. The stars trailed during the exposure due to Earth's rotation.

Notice the rich blue-green color of Comet Lulin in the telephoto image. Sunlight beating down on the comet's nucleus (core) vaporizes ice and chemicals locked in the ice to form a cloud called a coma. One of the chemicals liberated is cyanogen gas, which fluoresces green in sunlight. Cyanogen smells pleasantly of almonds, but it's a poisonous gas composed of one atom each of carbon and nitrogen. Most comets have cyanogen locked in their ice, waiting to be liberated by the gentle warmth of sunlight.

A time exposure picks up cyanogen's color with ease, but you won't see it with your eye until Lulin is closer and brighter. A few years back, Comet Machholz looked like an emerald haze through the telescope. Beautiful!

In the winter of 1910, astronomers detected cyanogen in Halley's Comet (right) using an instrument called a spectroscope, which can identify chemicals in comets, planets and stars by their "light fingerprint". Since Earth would pass through the comet's tail in May that year, alarmed news reports circulated that humanity might be asphyxiated by clouds of poison gas. Astronomers tried to get the word out that the tail was much too rarified to have any toxic affect. No matter. Most newspapers never published that story. Those seeking to make a profit on fears of death-by-comet-gas sold 'comet pills' to counter the ill affects. In the end, everyone lived. For more on Halley fears, you might enjoy this period article.


Watch the research satellite UARS cross the northern sky Saturday night (Jan. 24) starting around 6:10 p.m. UARS will be brightest when it's near the Bowl of the Big Dipper. Created with Stellarium.

Tonight should be clear again. If you're thinking of watching the space station's pass across the northern sky tonight (starting at 6:31 p.m.), consider going out 20 minutes earlier to spot UARS, the Upper Atmosphere Research Satellite. UARS will be crossing the northern sky around 6:12 p.m. and appear like a star one level dimmer than the stars of the Big Dipper. Not too dim, not too bright.


The UARS satellite is about 35 feet long. Photo: NASA

UARS was launched from the space shuttle in 1991 and carries instruments for studying the ozone layer (and holes in the ozone), wind and temperatures in the stratosphere, and energy output from the sun. Its mission is to find out how changes in Earth's upper atmosphere affects the planetary climate. While many of its instruments are no longer functional, you can still watch this remote laboratory cross the night sky 375 miles above your head.

Posted by: rking@duluthnews.com on 1/24/2009 at 12:17 PM | Comments (2) | Permalink

Go west young astronomers, go west

This map shows the western sky in late January at 7 o'clock. Look two outstretched fists to the right and above Venus to find the Great Square of Pegasus. Continuing to the right, you'll also come across the Northern Cross, now making its "last stand" in the northwestern sky before departing later this season. The familiar zigzag of Cassiopeia (top) is another handy sky guide. Created with Stellarium.

I noticed how nicely the planet Venus pointed to the Great Square of Pegasus the other night and figured it was worth one last look at this huge asterism, now in the western sky. It's been my experience that amateur astronomers pay more attention to what's coming up in the east than what's going down in the west. There is logic behind this. The higher a star or planet is in the sky, the less our turbulent atmosphere absorbs and distorts its light.

An imaginary arc called the meridian rules an astronomer's senses. The meridian begins due south at the southern horizon, passes overhead and ends due north at the northern horizon. Stars rise in the east, reach their highest point in the sky at the meridian, and then slide toward the western horizon. Amateurs watch the sky the same way they do a parade, anticipating and paying attention to what's coming up next, not what's passed.

Of course this isn't strictly true, and Pegasus is a good example. Now that Venus is in the neighborhood, you can take advantage of her bright assistance to find mythology's horse with wings.

Another constellation descending rapidly westward is Cygnus the Swan, better known as the Northern Cross. It stands perfectly erect in the northwestern sky during the early evening. The chart is drawn for 7 p.m. but to see the full cross before its foot is lost in the trees, go out earlier around 6:30 p.m. The Duluth-Superior area will see a bright flare from the satellite Iridium 41 at 6:29 p.m. Friday evening (Jan. 23) about halfway up in the southern sky.

You'll need a reasonably clear view to the south to find Comet Lulin near the Head of Scorpius Saturday morning (Jan. 24). This map depicts the sky around 6 a.m. looking southeast. Created with Stellarium.

For those who enjoy a frozen finger challenge, I invite you to set your alarm for Saturday morning just before 6 a.m. If you have a pair of 50mm binoculars (7x50, 10x50, etc.) or a telescope, you can try to spot Comet Lulin in the constellation Libra the Scales. It's not far from the Head of Scorpius the Scorpion. Warning! Lulin will not be a spectacle. Through binoculars, the comet will appear as a faint, fuzzy spot. Telescopes will show it much better as a pretty bright, compact glowing cloud. The tail that shows up in photographs is still too faint to be seen in modest telescopes.

As for me, I haven't decided whether to freeze my bones with some early evening observing or wait until the morning for Lulin. Tough choices, tough choices.

Posted by: rking@duluthnews.com on 1/23/2009 at 1:50 PM | Comments (1) | Permalink

Winter sky geometry

The Winter Hexagon extends all the way from beneath Orion to the
very top of the sky, and is best seen from 8:30 p.m. until
midnight. High clouds that drifted through the field during the
time exposure are colored orange-pink by light pollution
from the city of Duluth. Details: 17mm lens at f/2.8, 30-second
exposure at ISO 800. Photo: Bob King

What a tranquil evening yesterday. No wind, not too cold and a winter sky jangling with stars. The Winter Triangle, made up of Betelgeuse, Procyon and Sirius, cuts a very nifty slice of pie in the sky, but if you're yearning for more geometry with your stars, allow me to introduce the Winter Hexagon.

Winter boasts the greatest number of first magnitude (brightest) stars in the sky at any one time. Most of them occupy the same region, centered on Orion the Hunter. By a fortunate coincidence, seven of the brightest can be connected to form a very large, six-sided figure in the southern sky around 9 p.m. in late January. Here's the breakdown:

Auriga the Charioteer contributes Capella
Taurus the Bull - Aldebaran
Orion the Hunter - Rigel
Canis Major the Big Dog - Sirius, the brightest star in the sky
Canis Minor the Small Dog - Procyon
Gemini the Twins - Castor and Pollux

This map shows the constellations of the Winter Hexagon.
Created with Stellarium.

Since they're all bright, you can see the Hexagon from just about anywhere -- city, suburb or countryside. Those with a little darker skies, can use the Hexagon as a foundation for locating each star's "home" constellation.

I just like the whole glamorous look of it all. All that sparkle up above translates to a good feeling in the heart.

Posted by: rking@duluthnews.com on 1/22/2009 at 2:04 PM | Comments (2) | Permalink

Readers' photos; more space station passes

Lars Waldner of Duluth grabbed a very nice shot of the International Space Station cruising by Venus Tuesday night. For more space station times this week, please see below.

The planet Uranus is circled in this photo made Tuesday evening. Venus is the much brighter object to the right. The stars are short trails instead of points because they moved toward the west during the short time exposure. Compare this photograph to the chart of the two planets from Tuesday's blog. Photo: Lars Waldner

Andrew Kirk of Bishop, California photographed the sun,
distorted by the atmosphere and light cloud, as it set
over the Pacific. "I'm 56, and last week was the first time
I have ever watched the sun set into the ocean," said
Kirk.

We're glad you guys had your cameras at the ready. Thank you both!

OK, space station watchers, here you go. The station is first visible low in the western sky and moves toward the east.

* Thursday night, Jan. 22: A brilliant, high pass during twilight beginning at 5:34 p.m.
* Friday, Jan. 23: Another high, bright pass across the northern sky starting at 6:03 p.m.
* Saturday, Jan. 24: Bright pass across the northern sky beginning at 6:31 p.m.
* Sunday, Jan. 25: "    " at 5:23 p.m.

Posted by: rking@duluthnews.com on 1/21/2009 at 9:37 PM | Comments (5) | Permalink

Is Betelgeuse ready to blow?

This illustration gives you an idea of Betelgeuse's enormity. Put in place of the sun, it would be nearly as large as the orbit of Saturn. The inset photo was taken by the Hubble Space Telescope. Credit: Tom Callen, Cosmonova, Swedish Museum of Natural History, Stockholm

It's sad there's so much distance between us and Betelgeuse, Orion's second brightest star. To the eye, it's a flickering pink spark and no more. In all but the most powerful professional telescopes Betelgeuse remains a pinpoint. But if we could dissolve the 640 light years that separate Earth and star, we'd be awestruck at the sight.

Hovering before us would be a bloated sphere of fiery gas almost 1000 times the size of the sun and 135,000 times brighter. Over time we'd be able to watch it's atmosphere slowly pulsate, expanding and contracting like an enormous heart. Betelgeuse is a red supergiant star only 8.5 million years old, barely a teenager by stellar standards. Compare that to the sun, which is over four billion years old, and just now entering middle age.

The Hubble Space Telescope was the first to image the actual disk of Betelgeuse. The red "collar" is the star's outer atmosphere. Credit: NASA/ESA

Betelgeuse, which has a variety of pronounciations --BEET-el-jooz and BET-el-jooz are the most common -- is so large that it's consuming its hydrogen fuel at a rapid rate. As stars "cook" hydrogen in their interiors, they convert it into energy (starshine) and heavier elements like helium, carbon, oxygen and so forth. Giant stars cook elements all the way up to iron. Once they hit the "iron wall", they run out of material to burn. Iron can't be cooked to create heat and new materials. With no heat to counteract the ever-present pull of gravity, the star collapses, rebounds and tears itself apart in frighteningly powerful shock wave.

Such an event is called a supernova. I've been fortunate to track down several hundred of them in galaxies beyond the Milky Way over the past 25 years. While a supernova looks like an ordinary star, you're watching one of the biggest bangs the universe has to offer. It always gives me a thrill.

No one's seen a supernova in our galaxy for the past 400 years but Betelgeuse is a prime candidate to become one. It's big enough to cook up iron and blow bigtime. When you ask? Scientists estimate Betelgeuse is within about 10,000 years of exploding. Will it be tonight, next week, the year 4209 AD? When it goes, it'll be as bright as the half moon, visible in the daytime and cast crisp shadows at night. Even though Betelgeuse is many light years away, the explosion will send a pulse of ultraviolet light that could endanger future space travelers to the outer solar system. There's even a remote possibility the blast wave could alter the Earth's upper atmosphere.

Let's pull back a safe distance from Betelgeuse again. The next clear night, gaze across the light years into its baleful red eye, and cross your fingers the big show will happen during our lifetimes.

(Star size comparison diagram above from NASA)

Posted by: rking@duluthnews.com on 1/21/2009 at 12:35 PM | Comments (1) | Permalink

A remote planet within your grasp

The waning moon Tuesday morning brushes up against a red pine. Photo: Bob King

Nice to walk out the door this morning and see the crescent moon in the south before sunrise. I find the crescent the most eye-catching lunar phase. Don't forget -- tonight we have a fine pass of the International Space Station beginning at 6:14 p.m. just under the planet Venus in the southwestern sky. This would make a good photo opportunity for an enterprising photographer.

You can use brilliant Venus to help you find the outer planet Uranus from Jan. 20-23. The map is drawn for around 6:30 p.m. each night, and the black circle represents a typical binocular field of view. Uranus is moving too, but much more slowly, so it will stay in the same place during the interval. Illustration created using SkyMap software by Chris Marriott.

Venus will be our guide the next few nights to finding the planet Uranus. It's a fortunate thing that all the planets travel in nearly the same plane of the solar system. They're like runners on a track. The faster ones closer to the sun lap the further ones. That makes for lots of cool lineups called conjunctions. This week, Venus will be passing near the outer planet Uranus. If you've never seen Uranus before, destiny is knocking on your door.

Uranus is barely visible with the unaided eye from a dark sky location, but it's easy to see in binoculars. Since the planet looks just like a star, the problem is distinguishing it from all the other stars in the vicinity. Venus gets you close enough to make this task easier. The map above is about one binocular field of view wide. The little unmarked dots are stars, all of which are bright enough to be seen in most binoculars.

The planet Uranus is shown in true comparison size to Venus. Even though Uranus is four times the diameter of Venus, it's so much further away that it looks like a star in binoculars and a minute disk through a telescope. Illustration: Bob King

First, print out a copy of the map, grab a red or dim flashlight and go outside. Point your binoculars at Venus and set it off to one side of your binocular field. Try not to stare it! The glare will make dimmer Uranus harder to find. Now compare the map to the real view in the binoculars, and "star hop" your way from Venus to Uranus. If you find it, you deserve a big congratulations. Let us know via the comments links how it went.

I'll be out there the next clear night to try it myself and will update the blog with more tips if needed. Good luck!

Posted by: rking@duluthnews.com on 1/20/2009 at 2:08 PM | Comments (2) | Permalink

Earth as a planet

Looks like Mars, doesn't it? This 1.2 mile-wide crater is actually deep in the Sahara Desert. It's called Tenoumer Crater and lies on vast plain of ancient rock. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image over Mauritania on January 24, 2008. Credit: (NASA,Jesse Allen, NASA/GSFC/METI/ERSDAC/JAROS, U.S./Japan ASTER Science Team)

Most of the time this blog features information and photos of worlds beyond the Earth. We're looked at the planets, near and distant stars, asteroids, comets and quasars. Sometimes it's fun to turn our gaze Earthward and see our planet as one world among many. To help us do that today, I want to recommend a series of photographs taken by Earth-orbiting satellites featured on the Boston Globe website. They're guaranteed to pin your wow meter at high.

The Bear Glacier on the Kenai Peninsula along the Gulf of Alaska seen by the IKONOS satellite on August 8, 2005. IKONOS satellite image courtesy GeoEye.

The 23 images are just a small sample of some of the best images from NASA's Earth Observatory website. I scrolled through these last night and gained a better appreciation for our home planet's incredible diversity of landforms and environments -- both natural and those touched by the hands of humans.

Posted by: rking@duluthnews.com on 1/19/2009 at 1:42 PM | Comments (0) | Permalink

Meet Calgalleon and Gnarrangalleon

The Large Magellanic Cloud (LMC)(center) and Small Magellanic Cloud (SMC) glow in early dawn light from near Winton, Queensland, Australia. The Magellanic Clouds are two of the closest galaxies to the Milky Way, more than 10 times closer than the Andromeda Galaxy. Photo by Chris Schur and used by permission.

Anyone headed to Australia this week? If you plan a trip to the far, far south this winter, it's a perfect time to get acquainted with Calgalleon and Gnarrangalleon. These are the old names given by the Aboriginal people to the Milky Way's two brightest satellite galaxies. Calgalleon has to do with "woolly sheep". Today they go by the more familiar name of the Magellanic Clouds, named after Ferdinand Magellan's circumnavigation of the globe between 1519-1522. Magellan and the crew were the first Europeans to see them.

It was long thought that these two mini-galaxies orbited the Milky Way the way the Earth and planets orbit the sun. New research now seems to indicate that they're moving too fast to be captured by our galaxy's gravity. In that case, they're fellow travelers instead of galactic canines on a leash. The bigger one, the Large Magellanic cloud (Calgalleon), is in the constellation Dorado the Goldfish, and some 180,000 light years away. At 15,000 light years across, the LMC is about a tenth the size of our galaxy. Its sister, the Small Magellanic Cloud, is 210,000 light years from us.


An all-sky picture taken in infrared (dust-penetrating) light shows the flattened disk of our Milky Way galaxy. The Magellanic clouds are below and right of center. Credit: J. Carpenter, M. Skrutskie, 2MASS project, NSF, NASA

Notice that their shapes lack the nice spiral symmetry of the Milky Way. Both the LMC and SMC are classed as dwarf irregular galaxies. Dwarf doesn't mean dull when it comes to these two. Hundreds of star clusters and nebulas lie buried in these galactic smallfry, enough to keep telescopic observers busy for years.


Closer views of both the Large cloud (left) and a portion of the Small cloud (right). See below for a closeup of the Tarantula Nebula. Photos: NASA/ESA

The LMC is home to one of the largest known nebulas in the universe called the Tarantula, named after its spidery tendrils of dust and gas. The Orion Nebula is 24 light years across and just visible to the naked eye as tiny smudge below Orion's Belt. The Tarantula is 1,000 light years across, so big that if placed at the same distance as the Orion Nebula, it would cover 30 degrees of sky. That's one and half times the size of the entire constellation of Orion! How many millions of stars will congeal from this enormous bulk of gas and dust is anyone's guess. Suffice to say, it's the biggest star hatchery in the neighborhood.


The central region of the Tarantula Nebula in the LMC. New stars form from the collapse of dusty knots within the nebula. Photo: NASA/HST

The two clouds look like chunks of the Milky Way adrift among the stars. I saw the Large Magellanic Cloud only once, on a trip to view Halley's Comet in southern Peru in 1986. With my naked eye, it looked like a softly glowing cloud with a brighter center. To get at least a reasonably good look at them, you'd need to drive south until Orion was directly overhead -- a trip that would take you all the way to the equator. Southern hemisphere observers get the best view during their spring and summer (our fall and winter), when the clouds cycle around the southern pole star during the evening hours.

If you've been contemplating a trip to Australia and need one more reason to go, consider getting to know the Milky Way's best buds, Calgelleon and Gnarrangalleon.


This is a wide-angle view of the sky from Alice Springs, Australia during January evening hours, where the Magellanic Clouds are a showpiece this season. Created with Stellarium

Posted by: rking@duluthnews.com on 1/18/2009 at 2:57 PM | Comments (0) | Permalink

Space station returns to Northland skies tonight

This time exposure photo records a pass of the space station taken from my home last July. The ISS is the brightest satellite in the sky because it's the biggest (reflects more light) and orbits relatively near the Earth at an altitude of around 215 miles. Photo: Bob King

The International Space Station (ISS) returns to Northland skies tonight (Jan. 17) as it begins a series of evening passes. This evening's will be low but things will quickly improve over the coming week. The three-person crew, which has been aboard the station since last October, is conducting experiments and doing maintenance.

One crew member, flight engineer Sandra Magnus (left), has been working with the Advanced Resistive Exercise Device (ARED), which will allow astronauts many more exercise options than just the onboard bicycle and treadmill. Zero-G can have serious affects on the human body, including weakening of the bones. Exercise is crucial to staying healthy in space. The ARED functions something like a weigh-lifting machine but instead of weights, it uses vacuum cylinders and flywheels to create resistance and artificial gravity. Astronauts will soon be able to do squats, curls and bench presses.

When asked what motivated her to become an astronaut, Magnus said: "I can’t really think of a “alleluia” moment where I just had, like a lightning bolt hit me and say, hey, I want to be an astronaut. It’s something that I think came to me from the viewpoint of being able to be on the edge of something. I’ve always been interested in why things work and how things work Just the whole idea of exploring and learning new things just grabbed me and space was the place to do it." Learn more about the current mission here.


The International Space Station orbits above the blue Earth. Here you can clearly see the large solar arrays the station uses to generate electricity. Photo: NASA

Here's a list of upcoming space station passes. The times are for the Duluth-Superior region but will be very similar across the upper Midwest. The ISS will look like a bright "star" moving from west to east across the sky. You might notice it has an orangey hue. That's caused by light reflected off the gold-colored solar arrays. While you're out watching, keep your binoculars handy. If you follow the station as it fades into darkness near the end of its path, your binoculars will show it change color from yellow to deep red. That's the light of sunset reflecting off the station's exterior. Because the ISS is 215 miles overhead, the astronauts still see the sun long after it's disappeared for us ground dwellers.
 
Fun to think that as the station reddens and fades, Sandra and the crew get to witness yet another sunset, one of 16 sunsets visible every day in orbit. Nice perk!

* Tonight, Jan. 17 -- A low, brief pass across the southern sky starting at 6:26 p.m. and ending a minute and a half later.
* Sunday, Jan. 18 -- Another brief but brighter pass in the southwest starting at 6:53 p.m. While you're out, there will be a brilliant flare from the Iridium 80 satellite at 6:50 p.m., halfway up in the south-southeast. If you're in the right spot, the flare will be much brighter than Venus!
* Monday, Jan. 19 -- This pass will be two outstretched fists high across the south beginning at 5:46 p.m. Near the end of the pass at 5:49, the ISS will pass right over Orion's Belt. Twilight will be a factor during this pass.
* Tuesday, Jan. 20 -- An excellent, high and bright pass beginning at 6:14 p.m. with the station traveling from southwest to northeast. A good one to watch for that sunset color change as it fades in the eastern sky above Gemini the Twins.
* Wednesday, Jan. 21 -- Another brilliant pass starting in the northwestern sky at 6:42 p.m. and fading out directly above the North Star three minutes later. Another nice opportunity to share sunset with the astronauts.

(Photo of Sandra Magnus / NASA)

Posted by: rking@duluthnews.com on 1/17/2009 at 11:27 AM | Comments (0) | Permalink

Reflections on ice

Plates of broken ice lay stacked along the shore of Lake Superior in Duluth Friday morning. In the distance at right, a single ice fishing shack stands precariously close to the path broken by the icebreaker. Photo: Bob King / Duluth News Tribune

There are times in Duluth when you think you're living on another planet. That's what it felt like this morning along the shore of Lake Superior. An icebreaker broke a path to allow the last ships of the season to lay up in port. Cold air blowing over the freshly-exposed water created a wall of condensing vapor that rose from the lake like a firestorm.

Closer to shore, the ice sheet held tight, while tumbled stacks of broken ice lined the beach. Vapor, liquid and solid -- water ruled. These days of bitter cold and ice excite the nerve endings like no summer day can. You move quickly, keep your comments brief and think fast or risk frozen frozen fingers and feet. We're fortunate to live in a city with such extremes of climate, and share our icy heritage with several other solar system locales. The one that came to mind today was Jupiter's moon Europa. This ball of ice is about the size of our own moon and orbits Jupiter every 3 1/2 days.


Huge water ice floes cover the surface of Jupiter's moon Europa (inset). Look closely and you'll see that some of the floes were once part of one piece but later broke into separate sheets when disturbed from below. Photos: NASA/JPL

Early photos of Europa taken by the Voyager spacecraft in 1979 showed strange cracks in its bright surface. More detailed pictures from the Galileo mission in the 1990s revealed an icy crust fractured into thousands of ice floes and blocks that resemble those in our planet's polar seas. The floes have clearly been on the move in the past, lubricated perhaps by liquid water from below. No one knows for certain when they'll slip and slide again. The temperature on Europa's surface is a cool -260 F, cold enough to keep a pizza frozen for eternity. But the moon's interior is warmer, because it's flexed by the combined gravity of Jupiter and its other inner moons. Instead of a solid ball of ice, Europa appears to have a liquid ocean beneath its chilly crust.

When scientists look at potential habitats for life beyond the Earth, their eyes turn not only to Mars but also to Europa, stocked with a hidden, salty ocean like some Chicken Soup for the Interplanetary Traveler. We know that extreme forms of life on our planet don't need sunlight to survive. Think of the bacterial colonies drawing energy from chemicals that bubble up from those black smoker vents deep down in the ocean. There are even rock-eating bacteria found thousands of feet beneath the ground.

I'm betting on life on Europa. If future space travelers could bring a sample back to Earth, chances are it would feel right at home in Duluth .

Posted by: rking@duluthnews.com on 1/16/2009 at 1:11 PM | Comments (0) | Permalink

Is there smelly life on Mars?

A map showing methane gas concentration in Mars' atmosphere. Credit: Trent Schindler/NASA

From NASA press releases today (Jan. 15): Some thought-provoking possibilities

Mars today is a world of cold and lonely deserts,
apparently without life of any kind, at least on the surface. Indeed
it looks like Mars has been cold and dry for billions of years, with
an atmosphere so thin, any liquid water on the surface quickly boils
away while the sun's ultraviolet radiation scorches the ground.

The situation sounds bleak, but research published today in Science
Express reveals new hope for the Red Planet. The first definitive
detection of methane in the atmosphere of Mars indicates that Mars is
still alive, in either a biologic or geologic sense, according to a
team of NASA and university scientists.

On Earth, methane is produced in massive quantities by animals such as cows,
sheep and goats.

Giant telescopes from Earth and NASA's Mars Reconnaissance Orbiter have spotted
a haze of the gas surrounding Mars, and according to some scientists this can
only point to the presence of life on Mars.

"Methane is quickly destroyed in the Martian atmosphere in a variety
of ways, so our discovery of substantial plumes of methane in the
northern hemisphere of Mars in 2003 indicates some ongoing process is
releasing the gas," says lead author Michael Mumma of NASA's Goddard
Space Flight Center. "At northern mid-summer, methane is released at a
rate comparable to that of the massive hydrocarbon seep at Coal Oil
Point in Santa Barbara, Calif."

If microscopic Martian life is producing the methane, it likely
resides far below the surface, where it's still warm enough for liquid
water to exist. Liquid water, as well as energy sources and a supply
of carbon, are necessary for all known forms of life.

"Gases, like methane, accumulated in such underground zones might be
released into the atmosphere if pores or fissures open during the warm
seasons, connecting the deep zones to the atmosphere at crater walls
or canyons," he says.

"We observed and mapped multiple plumes of methane on Mars, one of
which released about 19,000 metric tons of methane," says Geronimo
Villanueva of the Catholic University of America in Washington, D.C.
Villanueva is stationed at NASA Goddard and is co-author of the paper.
"The plumes were emitted during the warmer seasons -- spring and
summer -- perhaps because the permafrost blocking cracks and fissures
vaporized, allowing methane to seep into the Martian air."

Read the complete release here.

Posted by: rking@duluthnews.com on 1/15/2009 at 7:27 PM | Comments (1) | Permalink

Bunny tracks beneath Orion's feet

Tracks of a snowshoe hare in the front yard this winter. Photo: Bob King

Every night my dog Sammy finds a rabbit to chase. Last night she lept into nearly three feet of snow at the sight of one. Came back empty-mouthed, as usual. That never stops her from trying. Another kind of rabbit makes its home in the winter sky beneath Orion, but unlike the kind Sammy chases, this one stays put.

Lepus the Hare can be found just below Orion on January evenings. This map was drawn for around 8 o'clock local time. Created with Stellarium. Rabbit from photos.com

The constellation is called Lepus (LEEP-us) the Hare, one of the 48 original constellations from the days of ancient Greece. While it has only two stars that are similar in brightness to those in the Big Dipper, Lepus is easy to find because it resides just below the familiar constellation of Orion the Hunter. If you can spot the Belt of Orion, direct your gaze an outstretched fist below it. That's where our wascally wabbit makes her nest .

In some legends, the hare is fleeing from the dog Canis Major (at left). Apparently Orion is after bigger prey. Created with Stellarium.

While drawings depict the form of a rabbit among the stars of Lepus, the figure reminds me more of a dragonfly. The topmost three stars form the dragonfly's tail while the bottom six or so fan out to form the wings.

There's a interesting legend about the Hare. Long ago in Greece, someone brought a pregnant hare to the island of Leros. At first everyone thought this was a good thing and raised the litter after litter of rabbits. Before long, the island was overpopulated with the little furry creatures. Eventually the residents had to clear them off the island. They put an image of the hare in the stars below Orion as a reminder that sometimes you can get too much of a good thing.

I'm afraid my dog just wouldn't understand that sentiment.

A time-exposure photo taken last night of Orion
and Lepus. Details: 35mm lens at f/2.8, ISO 800,
15-second exposure. Photo: Bob King

Posted by: rking@duluthnews.com on 1/15/2009 at 2:02 PM | Comments (0) | Permalink

This cloud can write

Andrew Kirk in Bishop, California has an eye for patterns in nature and is always on the lookout for atmospheric oddities. He sent this picture he calls "cirrus writing" I thought you'd enjoy. Unusual and beautiful displays of nature seem to have a way of appearing in the most commonplace settings, don't they?

Check back later today. We'll be visiting with a rabbit on the run in tonight's sky.

(Your photos are always welcome. Send jpg images to: rking@duluthnews.com)

Posted by: rking@duluthnews.com on 1/15/2009 at 8:14 AM | Comments (0) | Permalink

Bask in her radiance

High and bright, Venus is unmistakeable during evening twilight in January. This map is drawn for 5 o'clock local time. Created with Stellarium.

It's been a long, slow climb but Venus has arrived at the mountaintop. Today the planet reaches its greatest elongation (greatest apparent distance) from the sun in the evening sky. While its true distance from the sun varies little during it 225-day orbit, from our perspective here on Earth, Venus has been moving up and away from the sun since last July. Now six months later, it stands high after sunset, the first "star" of the night.

I'll bet many if not all of you reading this have seen it in the southwestern sky during the evening hours. Not until the pre-dawn skies of June will Venus appear as far removed from the sun as tonight.


As Venus revolves around the sun, it shows phases just like the moon. Tonight Venus (A) will appear farthest from the sun in the sky because we see it well off to the "left side" of its orbit at a right angle. In the coming weeks, that angle will get smaller, as Venus (B) approaches Earth and lines up more closely with the sun. After March 27, Venus will swing to the right of the sun, moving into the morning sky (C). By May 5, it will again be farthest from the sun (D). On Jan. 12, 2010 it lines up with the sun once more but on the far side of its orbit (E). Illustration: Bob King

Venus sets for our region at about 9 o'clock, more than four hours after sunset. By twilight's end, it's bright and high enough to cast shadows. I read about this and finally checked it out for myself a couple years ago. To see this special shadow, you need to be somewhere where there are no artificial lights (or moonlight) to muck things up. A snow-packed road or field provides a perfect backdrop. The lighter-toned, the better. Once your eyes are dark-adapted, take a look for your shadow. I had trouble seeing it unless I made quick back and forth moves while looking over my shoulder. Then it popped into view -- but I had to keep moving.

If you do see your Venusian alter-ego, you might notice that the shadow edge is very sharp in contrast to the soft-edged shadows cast by the sun and moon. Venus is a brilliant point of light, and point sources cast hard-edged shadows. Bright disks are like thousands of tiny points of light, each of which casts a shadow that overlaps and fills in the shadow of its neighbor, creating a blurry outline. Read more about shadows here.


As Venus orbits the sun, we see it go through phases as our perspective changes week to week, month to month. Through a telescope tonight it will look exactly like a half moon. Notice that Venus is largest (and closest to us) when it's a crescent. Compare to the diagram above. Photos: Statis Kalyvas

Since Venus is closer to the sun, it takes a shorter time to complete an orbit. If you look at the diagram, you'll see that it'll catch up with the Earth (at B) and lap us in late March. As it does, its phase will narrow to a crescent while at the same time growing ever larger as it gets closer. After March 27, Venus will swing past the Earth and appear on the other side of the sun in the morning sky.

I know it'll be 25 below tonight, but Venus will dazzle. If you do the shadow mambo you might just stay warm enough to see your dark side.


The "double planet" of Earth and moon as you'd see them through a pair of binoculars from the cloudtops of Venus tonight. The two would appear as a brilliant starlike pair. Created with Stellarium.

Posted by: rking@duluthnews.com on 1/14/2009 at 12:56 PM | Comments (2) | Permalink

Catch a comet and a spy satellite

Comet Lulin on December 31. The blue color is caused by fluorescing gas in sunlight. Both dust tails are faintly visible on either side of the comet's coma. The nucleus or core of the comet is hidden within the bright, white dot at the coma's center. More photos here. Photo credit: Michael Jaeger

Slowly but surely a binocular comet is heading our way. Comet Lulin was discovered by Quanzhi Ye, with help from observing assistant Chi Sheng Lin, on images taken with a 16-inch telescope at Lulin Observatory in Taiwan on July 11, 2007. Ye, a student at Sun Yat-sen University in mainland China, was only 19 at the time. At first thought to be an asteroid, later photos showed a telltale fuzzy coma (gas and dust that form the head of a comet), hallmarks of a comet. Asteroids are miles-wide boulders that look exactly like stars in most telescopes, while a comet contains ice that vaporizes as it approaches the sun. The ice liberates embedded dust and gives comets their fuzzy appearance.

In addition to astronomy, Comet Lulin co-discoverer Quanzhi Ye enjoys classical music and plays violin. Courtesy: Quanzhi Ye.

Amateur astronomers watched Lulin creep through the zodiac constellation Sagittarius last summer when it was visible in modest telescopes. The comet passed closest to the sun last weekend and is now headed toward the Earth. It's been brightening all along, and is currently in the morning sky in the constellation Libra the Scales. I saw it faintly in binoculars last week.

Comet Lulin will gradually brighten as it approaches our planet, becoming an easy binocular object in late February during the evening hours. From a dark rural sky, it should be visible with the naked eye.

Lulin's orbit is a bit unusual. While it travels the very same path as the planets through the zodiac constellations, it's moving in exactly the opposite direction. Planets move from west to east across the sky, but this comet is speeding along from east to west.

Comet Lulin on January 2 in a photo taken by Ernesto Guido, Giovanni Sostero and Paul Camilleri. Check out their comet blog for more.

We also get a rare opportunity to see not just one but two tails. Since Lulin moves along side us in its orbit, we'll get to see dust boiled off from solar heat in all directions around the nucleus. Because of perspective, this will give Lulin the appearance of a poor man's shishkebab, with a tail sticking out of either side of the coma. Astronomers call the second tail an anti-tail. They're quite rare and usually faint, but as you can see from the photos, the double tail has already sprouted.

Because Comet Lulin was discovered through the efforts of both the Taiwanese astronomers and Quanzhi Ye in China, it's recently acquired a new name, the "Comet of Cooperation". Let's hope the spirit of cooperation continues with a good run of weather next month. I'll update this blog regularly with new information on our fuzzy visitor. You can also find more details at Quanzhi Ye's blog .

Watch for the Lacrosse 3 spy satellite to pass across the top of the Square of Pegasus Tuesday night (Jan. 13). It will look like a modest "star" moving from west to east at the times shown. The satellite is almost the same brightness as the star it grazes in the upper left corner of the Square. Created with Stellarium

Cold weather often brings clear skies. If you're brave enough to step out tonight, we have a good opportunity to spot one of our country's spy satellites. It's called Lacrosse 3 and you can find out more about it here. Use the map and be sure to go out a little early to get oriented. Lucky for us, the satellite passes right next to the top left star in the familiar figure of the Square of Pegasus, located about 3-4  outstretched "fists" above Venus.

Posted by: rking@duluthnews.com on 1/13/2009 at 12:16 PM | Comments (0) | Permalink

Bullseye!

A colorful, 3-ringed corona surrounds the moon Sunday night. Coronas typically occur in altocumulus and cirrocumulus clouds. In order to capture the color and detail of the corona, the moon is greatly overexposed in all the photos. Details: 35mm lens at f/2.8, 2-second exposure at ISO 400. Photos: Bob King

I'm almost ready to give up. For the past few days I've attempted to write about telescopes and a bright winter comet but my brain's been lassoed by the moon. True story. I shot some manmade moon coronas through my iced-up front door Sunday night. Later, as I went to take out the garbage, a real corona smacked me upside the head. Thin clouds moved in quickly around 10:30 p.m., creating a series a rapidly changing coronas around the moon. I've seen many coronas over the years but these were astounding in their vivid colors, number of rings and ever-changing size.

In five minutes, the best clouds had moved on, and while the corona persisted for at least another hour, the wildly colorful varieties were history. Rainbows and haloes get all the glory but when conditions are right, these little bullseyes more than hold their own.

Take a look at the weird shapes the corona took on as fresh clouds blew by. In the photo at right, the water droplets were so fine at the edge of the cloud, that the corona became enlarged in that direction. The tinier the droplets, the bigger the corona.

Coronas form when very fine water droplets or ice crystals in clouds diffract light from the sun or moon. The droplets are so tiny, they're similar in size to the waves of light itself. Light waves bound off the droplets, and just like waves in a pond, cross through one another. Where two wave crests meet and reinforce each other, a bright fringe or circle forms. Where a trough and a crest meet, a dark fringe is created. Each color in white light is diffracted a little differently by the droplets, creating a series of small colorful rings of varying brightness. Red light is diffracted to the outside of a corona, while blue fills the space in between.

I know it looks unreal but the colors were at least as rich and true as what's shown in the photo. What a sight!

Haloes are at least four full fists wide, but coronas are much smaller, usually less than one outstretched fist. The most striking colors occur in clouds where all the droplets are of the identical size. If the drops are all extremely small, the coronal rings are larger than those created by identical large droplets.

In more typical clouds, droplets come in a mix of sizes. Those create multiple, overlapping coronas which blend together into a pasty disk. In the photos, you'll see that the shape of the corona kept changing. Clouds were on the move and new ones formed quickly. The freshly formed clouds must have had identical droplet sizes, perfect material for light to zing off and diffract.

Hungry for a corona but don't have the right clouds? Ice crystals on your windows diffract light just like the ones in the clouds. Try looking at the moon or sun through an icy or frosted windowpane. This picture was taken through the glass of my front door. I moved the camera around to find the spots where the corona would be most colorful, and took a whole series of photos. Give it a try yourself. Details: 105mm lens at f/2.8, ISO 800 at 1/50 second. 

So there you have it. Thanks to the moon, not only have I postponed blogs on other topics, but I nearly forgot to take out the trash.

Posted by: rking@duluthnews.com on 1/12/2009 at 2:24 PM | Comments (2) | Permalink

Bright satellite flares begin this week

A time exposure of an Iridium satellite flare taken last summer. The flare started on the right side of the trail, gradually brightened to a peak (center of trail) and then faded. The Iridiums are in high orbits. That's why they appear to move more slowly across the sky compared to the shuttle or space station. Photo: Bob King

Hundreds of active satellites crisscross the sky every day and night. Many are used for communications, others are spy and research satellites. One particular group, called the Iridium constellation, is a array of 66 telecommunications satellites that provides voice, data and paging services around the world. If you're a researcher at the Amundsen-Scott South Pole Station in Antarctica, chances are you’re using one of these satellites to get your calls.


An Iridium satellite (about 12 feet long), showing the three main
antennas. An artificial flare was created by aiming a flash at the
foreground antenna. Photo: Daniel Deak

One thing that sets Iridium satellites apart from most others is their silver-coated Teflon main antennas. These reflect sunlight so well, that if an Iridium happens to be in the right part of the sky with respect to the sun and an observer on the ground, that observer will witness a short, brilliant flare of sunlight off one of the antennas. Called Iridium flares, some are much brighter than Venus.

I’ve been out and spotted a few by surprise without knowing at first what I was seeing. Supernova? Airplane? Now I’ve come to recognize the pattern. A flare appears like a slow-moving new “star” that grows brighter and brighter until you think it’ll pop. A few seconds later the “star” fades back to invisibility. Depending on how dark your sky is, flares last from a several seconds up to 15 seconds.

Over the next few nights, we’ll have an excellent opportunity to witness a number of Iridium flares. While the times and location apply to the Duluth-Superior region, you can find prediction times for where you live by checking out the Heavens-Above website. After you log in, click on the Iridium flares for the next 7 days link. Or you can download free software to get detailed predictions and explore all things Iridium at this comprehensive website.

Flares are a lot of fun to watch, and I guarantee you’ll amaze your friends once you convince them to stand in the cold for a few minutes. Remember to go out at least five minutes before the predicted times to allow your eyes time to adapt to the darkness, and to point yourself in the right direction. You'll find the anticipation a pleasure in itself.

* Sunday night, Jan. 11 -- Iridium 10 flare at 5:48 p.m. Look toward the south-southwest (SSW) three outstretched fists above the horizon.

* Monday night, Jan. 12 -- Iridium 13 flare at 5:42 p.m. Same direction and height as last night's.

* Wednesday night, Jan. 14 -- Iridium 40 flare at 7:05 p.m. Look toward the south-southeast (SSE) three fists above the horizon. This one should be MUCH BRIGHTER than Venus!

Posted by: rking@duluthnews.com on 1/11/2009 at 1:27 PM | Comments (0) | Permalink

A striking lunar halo

A full 360-degree ring around the moon Saturday night. This was a classic 22-degree halo, created by light bent by millions of microscopic, hexagonal ice crystals in cirrostratus clouds.  Details: 16mm lens at f/2.8, 2.5 second exposure at ISO 200. Photos: Bob King

An odd, oval glow around the planet Venus last night caused by high clouds. Was it a Venus corona? Details: 200mm lens at f/2.8, 2-second exposure at ISO 800.

I hope you got to see the huge halo around the full moon last night. It lasted for hours. Clouds threatened early (right) but the moon prevailed. After making a few photos of the scene, I put on skis and enjoyed a run down the trail. Around 9:30, it looked like the halo might fade away, but a half hour later around it reformed. Even Venus was surrounded by an odd oval glow. While the stretchy shape was faintly visible with the eye, it showed up better in the camera. What exactly was this glow around the planet? I'm guessing it was a little corona, similar to the ones we sometimes see around the moon.

Amateur astronomer Jim Schaff of Hermantown has been patiently recording the changing size of the moon as it orbits the Earth. Schaff created this wonderful comparison panel showing the full moon in May 2008 at apogee (furthest from the Earth) and near perigee (closest to Earth) two nights ago. Seeing the two moons side by side illustrates the size difference very effectively.

"The full moon has its own beauty," said Schaff, "even if it blocks the view of most other astronomical sights."

Posted by: rking@duluthnews.com on 1/11/2009 at 9:18 AM | Comments (0) | Permalink

Good night for howling

The full moon will shine from the constellation of Gemini the Twins Saturday night (Jan. 10). This map is drawn for around 8 o'clock local time. The bright stars Castor and Pollux in Gemini lie to the left and above the moon. One outstretched fist below and to the right will take you to Procyon, the brightest star in Canis Minor, the Little Dog. Created with Stellarium.

You thought the moon looked bright shining over a snowy landscape last night? Try looking at it in a telescope. I did and came away with an eyeful. More like a black eye. Magnified 75 times, the nearly full moon was a glaring ball of cold fire. When I finally turned away, the pupil in my "moon" eye had constricted to a pinhole, leaving me nearly blind for a minute or two. Amateur astronomers know that before they turn their gaze to the moon or a bright planet, they'd best look at the fainter star clusters and galaxies first, or risk losing their well-earned night vision sensitivity.

Tonight the moon is full at 9:27 p.m. Central time. If it's clear, you may be reminded of the extra intensity of December's moon, the closest full moon of 2008. January's Full Wolf Moon is the closest full moon of 2009. Compared to more distant ones, tonight's moon will be 14% wider and 30% brighter. Add in the snow and you've got light enough to read a newspaper outdoors or hop on the trail for a moonlight ski.

The moon's orbit around the Earth is an ellipse instead of a perfect circle, so its distance from our planet varies over a month's time. Tonight it happens that the moon is both full and at its closest (called perigee) at the same time. Big and bright is the order of the night.


With your naked eye alone, you might see more than you'd expect on the moon's face. The lunar seas are easy, but with focus and concentration, you may also be able to spot several of the bright rayed craters (see below) as well. Binoculars will make easy work of them all. Created with Stellarium.

While you're out, why not try to see how many features you can discern on the moon's wide-open face? The easiest to see are the dark patches called lunar seas, enormous lava-filled basins created by the impact of sizeable asteroids four billion years ago. The white regions are the even older lunar highlands. A telescope reveals they're saturated with impact craters. Don't expect to see many craters tonight though -- at full moon, the sun shines directly over the lunar landscape, casting short shadows that hide behind rocks and rims. With no shadows to show texture, most craters at full moon look like little more than faint rings.


This map identifies many of the lunar seas. The biggest is the huge area around Aristarchus and Kepler called the Ocean of Storms. The moon's eyes are formed by Serenity and Tranquillity. The first astronauts on the moon landed on the Sea of Tranquillity on July 20,1969. Illustration, photo: Bob King

For those who love a challenge, the smallest white spots on the moon are the rayed craters of Copernicus, Kepler, Aristachus and Tycho, all named after famous astronomers of the past. Tycho looks like an unresolved white area near the bottom of the moon. The others stand out better against the gray-colored seas, which are also known by the latin name of mare (MA-ray), as in Mare Serenitatis, Sea of Serenity.

Whatever the weather by you, I hope you have a most tranquillitatis evening with the moon.

It looks like this photo was shot in the middle of the
day. It was taken last night under bright moonlight. The
Big Dipper stands on its Handle above the house. 
Details: 20mm lens at f/3.5, 12-second time
exposure at ISO 200. Photo: Bob King

Posted by: rking@duluthnews.com on 1/10/2009 at 11:31 AM | Comments (2) | Permalink

Illegal astronomy

A partial halo rings the gibbous moon Thursday night (Jan. 8). Orion is visible to the lower left while the Seven Sisters star cluster lies to the right of the moon. Photo: Bob King

I used to be able to drive with my headlights off. Not that I recommend this, but when the moon is near full and the snow is thick on the ground, you can find your way down a country road without the aid of headlights. When my kids were younger, I'd occasionally shock them by turning off the lights briefly and driving by moonlight. Kids love surprises.

Last night I noticed how well I could see into the distance in moonlight so I turned off my lights. Or tried to. New cars won't let you do this. Technology insists we be absolutely safe and secure at all times. Disappointed but not completely defeated, I took a walk later to marvel at the radiance.

This diagram shows how hexagonal ice crystals bend light from the moon or sun to form a halo. Each one of the millions of crystals add a little bit of light to the final bright ring. To learn more about haloes, click here and here. Illustration: Donalbein (with my own annotations-BK)

The crystals are common in cirrostratus clouds. Sometime around 10 o'clock, a few high clouds spread across the sky and created a very temporary lunar halo. Part of a halo really. Just a smile's worth. The ice crystals that cause haloes are hexagon-shaped and cylindrical. Imagine millions of cut-up pencils, but so small as to be barely visible to the eye. Light from the moon or sun strikes these floating, gently-spinning crystals and is refracted or bent as it passes through them. There are so many crystals all bending light the same way that they concentrate it into a ring or halo some four outstretched fists across. This is called a 22-degree halo because that's the distance from the moon to the halo's edge.

Be sure to block the sun with you hand! This is the view of Earth along with Mercury and Jupiter as you'd see them at 9 p.m. Friday night (Jan. 9) from the surface of the moon. Created with Stellarium.

Last night's halo lasted only 15 minutes. The cirrostratus clouds responsible for this brief display moved on and clear sky returned. On Saturday night the moon will be full. You might remember we talked about how the phases of the moon and the Earth were complementary. When the moon's a thin crescent, the Earth appears "Full" as seen from the moon's surface. As the moon has waxed toward full phase this week, the Earth's been slimming down to a crescent as it approaches the sun in the lunar sky. This fascinating orbital yin-yang happens every month of the year.

Posted by: rking@duluthnews.com on 1/9/2009 at 11:25 AM | Comments (1) | Permalink

Some like it hot

One of winter's joys is to warm up again after being cold. We heat our home with oil and supplement with a woodstove. When I'm cold through and through after being out on a subzero night, I'll get a fire going in the woodstove. Once it's pulsing with the sound of chugging air, I know that good, bone-warming heat is on its way. I love reading a book in the glow of the stove. If I melt into sleep, all the better.

My friend Will sent me photos of his burn pile from the other night. He had a good time in the cold, staying near the fire while watching the moon battle the clouds overhead. We all like the feeling of having survived extremes of heat and cold. Another friend from the West Coast excitedly told me how he and his wife enjoyed getting blasted by a 6-below-zero wind in Chicago over Christmastime.

The following is a list for temperature extremophiles. Because I'm more in the mood for warm thoughts, the list focuses only on extremes of heat. We'll take a look at the chilly end of the spectrum in another blog. All temperatures are in degrees Fahrenheit.

The center of a lit cigarette is 1110 degrees. Drawing on it raises the temperature to 1290. Credit: photos.com

Candle flame at 1830 degrees. Hotter than
I thought. Credit: Matthew Bowden

Flames in Will's burn pile a toasty 2000 degrees. Credit: William Wiethoff

Different settings on a Bunsen burner, used in high school chemistry labs, produce flames that range in temperature from 2372 to 2912 degrees. This is also the temperature of the coolest stars. Credit: Arthur Jan Fijalkowski

Flames from the solid rocket boosters used during a space shuttle takeoff burn at 6000 degrees.

Now we're getting warmer. The surface of the sun is
11,000 degrees.The hottest stars are around 50,000
degrees. Credit: Bob King

Surprisingly, lightning is actually hotter than the sun with a temperature of 50,000 degrees. Credit: Mircea Madau

Gas swirling around a black hole is heated by friction to hundreds of millions of degrees before it's sucked in and disappears forever. Credit: NASA

When a star explodes as a supernova, temperatures can soar briefly to 3 billion degrees. Credit: NASA

OK, here it is -- the hottest thing in the universe! We don't have a direct photo of it but this map of the entire sky shows the radiation left over from the Big Bang, the origin of the known universe. A tiny fraction of a second after the Big Bang the temperature of the expanding fireball was 100 million million million million million degrees. That's billions of times hotter than any currently known object in the universe. Pretty cool, eh?

Posted by: rking@duluthnews.com on 1/8/2009 at 2:22 PM | Comments (0) | Permalink

Galileo would be tickled

A Galileoscope that will soon become available to interested skywatchers. Photo: IYA 2009

Last week I wrote about the International Year of Astronomy (IYA 2009) and one its outreach programs called the Galileoscope Project. This particular project's goal is to create a high quality, affordable telescope kit for $10 and make it available to everyone. Checking on the status of the scope, I discovered a useful link in case you're interested in buying one.

I'm really curious about this instrument so of course I got hooked up right away. If you'd also like to be notified when the scopes become available later this month, click here and you'll be taken to a site where you can sign up for an e-mail notification.

Posted by: rking@duluthnews.com on 1/7/2009 at 8:25 PM | Comments (1) | Permalink

A bigger, faster Milky Way

The Milky Way (modeled at left) just moved into first place as the biggest galaxy in the neighborhood, even larger than the Andromeda Galaxy (right). Credit: NASA

 If the Milky Way wasn't big enough already, Mark Reid of the Harvard-Smithsonian Center for Astrophysics has recently discovered that it's 15% larger and contains half again as much mass (weight) than we knew. This vaults our home galaxy to the Big Kahuna in our local cluster of galaxies. Astronomers had long thought the Andromeda Galaxy was dominant, but it's now in second place behind the Milky Way.

Reid and his colleagues mapped the motion of a group of stars in the Milky Way's spiral arms from different vantage points in Earth's orbit around the sun. When his team crunched the numbers, they discovered that our galaxy is spinning around its center at 568,000 miles per hour instead of 492,000 mph, a speed based on older, less accurate methods of measurement.

Knowing the speed, scientists could re-determine the Milky Way's diameter and weight. So yes, we have the most stuff, but that knowledge comes with responsibilities. I'll explain in a moment.

Members of the Local Group of galaxies include the Milky Way (center), Andromeda and a host of smaller ones. They all feel one another's gravity and hang together in space like a star cluster, but on a much larger scale. Illustration: Richard Powell

Our galaxy is one of at least 35 galaxies in a gravitationally bound cluster called the Local Group. We buzz around together like very slow-motion bees in a 5-million-light-year wide beehive. Scientists studying the motions of the Milky Way and Andromeda Galaxy learned years ago that the two were headed on a collision course in the distant future.

A view out the kitchen window in the far future will 
include an up-close-and-personal look at the Andromeda Galaxy,
as it nears its collision with our own galaxy. Illustration: 
Gary Meader and Bob King, photos: NASA and photos.com

The Andromeda Galaxy is zooming toward us this very day at 300,000 miles per hour, and will merge with our galaxy in about two to three billion years, creating one humongous Milkomeda (milk-OM-ed-uh). Don't worry too much about crashing stars -- the space between them is so vast, few if any will collide. Gas clouds however are large enough to mash into one another and birth a brand new generation of stars. Close encounters and mergers of galaxies are often accompanied by these "stellar fireworks" of creation.

Anyway, because the Milky Way is heavier that expected, it has more gravitational pull. That means it will tug on Andromeda harder and more directly, shortening the time until Merger Day. You probably won't be around in 2,000,002,009 A.D. but if you're curious what your descendants might see, take a look at this video of the simulated collision. It's a cosmic ballet par excellence.

Posted by: rking@duluthnews.com on 1/7/2009 at 12:58 PM | Comments (0) | Permalink

Anatomy of a hunter

Orion (at right) stands watch over the moonlit landscape last
night. Sirius the Dog Star is at center left. Details: 20mm lens
at f/2.8, ISO 800, 15-second time exposure. Photos: Bob King

Why did I go out last night? The house was warm, and my younger daughter and I had just finished watching a football game. Yet the sky was clear, and the dog needed walking. Seeing Orion due south in a moonlit sky was inspiration enough to bring out the camera for a brief photo session. By the time I was done, claws of subzero air were creeping up my legs and back.

Orion the Hunter is such a familiar constellation, and has much to offer for naked eye, binocular and telescope users. His belt and boxy outline are easy to spot. And who doesn't like to say the word "Betelgeuse"(BEET-el-jooz)? Bright Betelgeuse flashes at his right shoulder while Rigel marks his left knee.


Once you add the shield, club, head and knee, Orion begins to assume a more
human form.

There's still more to Orion. As he parades across the sky, the Hunter carries both a shield and a club. The shield is thrust out to the right of the main Orion figure and is best seen from a dark site, where its 10 or so little stars bear a good resemblance to one of those ancient Roman shields. Orion raises a club high in his other hand just above Betelgeuse. Armed and ready, our Hunter has an air of caveman authority.


The mythological figure of Orion the Hunter in another guise.
In this illustration from Burritt's Geography of the Heavens, he
holds a lion's skin instead of a shield.

Tucked between both upraised arms is a small triangle of stars that form Orion's head.
As with so much Greek mythology, there's more than one version of a story. In some depictions, you'll see Orion holding his club as usual, but in his other hand he holds the skin of a lion. If 21st century Minnesotans could design Orion's hunting bling this winter, we'd probably picture him with a fishing pole in one hand and an ice auger in the other. Happy hunting!

Posted by: rking@duluthnews.com on 1/6/2009 at 2:09 PM | Comments (6) | Permalink

The matter of the missing dust

Astronomers were taking pictures of a much larger, closer galaxy, called NGC 253, when they spied these two galaxies in the background. The otherwise invisible dust tendrils of the smaller galaxy are silhouetted against its neighbor. All photos: NASA, ESA and the Hubble Heritage Team

I came across the first of these three images of galaxies hovering in front of background galaxies just a few days ago, so I went looking for more. They're all taken by the Hubble Space Telescope. The bright parts of galaxies consist of billions of unresolved stars, while the dark lanes are dust silhouetted against vast starclouds. Galaxy dust is created when stars evolve and either shed or explode their outer layers. This rich "seasoning" gathers in great clouds, which later congeal into new generations of stars.


NGC 3314a (foreground) and 3314b lie about 140 million light-years from Earth, in the direction of the southern hemisphere constellation Hydra. The bright blue stars forming a pinwheel shape near the center of the front galaxy have formed recently from interstellar gas and dust.  

In these remarkable photos, much, much more is revealed than normally meets the eye. Here we see the foreground galaxies in silhouette against the background ones. Looking at pictures like these, scientists are amazed at what they've been missing. In the first photo, long tendrils of dust vastly increase the dimensions of what was thought to be a small galaxy. Astromomers have never seen dust this far beyond the visible edge of a galaxy's disk.


The galaxy pair called AM1316-241, 400 million light-years away in Hydra, consists of a spiral galaxy (left) in front of an elliptical galaxy. The background elliptical silhouettes dust lanes around the spiral that might otherwise go unseen.

Dust has a big effect on a galaxy's brightness, an important factor in calculating it's distance. Astronomers might be wondering about now whether they need to go back and tweak their equations. If these galaxies are bigger than they appear, perhaps they're also closer than our original estimates. Aside from the science, the photos are just plain beautiful. They show us how the universe allows a glimpse of its inner workings to the prepared eye.

(It also doesn't hurt to have a really big telescope.)

Posted by: rking@duluthnews.com on 1/5/2009 at 9:08 PM | Comments (0) | Permalink

Cluster heaven

You can use this map to help you find Auriga. It's drawn for Monday night (Jan. 5) around 7 o'clock. Auriga is shaped like a child's drawing of a house lying on its side. It has one bright star, Capella, that twinkles high in the east during the early part of the night. Created with Stellarium.

I should have probably alerted all of you to this earlier but there were so many other things happening in the sky. We've touched on the constellation Auriga the Charioteer before and its bright luminary Capella. Tucked insides the confines of the Auriga's pentagon is a bundle of star clusters, several of which are visible in binoculars. The moon is not yet too bright to give these a try from your backyard, but if you have to wait several evenings until the next clear sky, then hold off until after full moon. Auriga will be around all winter. If you're lucky you may even get a warm night for viewing.

The clusters are named "M" objects because they are belong to one of the first catalogs of night sky objects discovered with early telescopes. M stands for Messier, as in Charles Messier, an 18th century French observer who loved to hunt the night sky for comets. To avoid confusing fuzzy objects like galaxies and clusters with comets, he cataloged and described each with a number. They're the Messier (MESS-ee-ay) objects, and there's 110 of them. One of my first obsering milestones as a teenager was observing the entire catalog. Since I lived in the Chicago area, I had to wait until our family vacationed in northern Wisconsin to find some of the dim ones.

This closeup of Auriga shows our showpiece star clusters, M36, M37 and M38. Use binoculars or a small telescope to find them. Created with Stellarium.

Most are visible in small telescopes and binoculars, some with the naked eye. The Seven Sisters cluster is M45 while the Andromeda Galaxy hails by M31.

The three Messier clusters in Auriga are rich agglomerations of stars like the Seven Sisters. They contain at least 100 to 150 stars apiece. M36 and M38 are approximately 3500 light years away, while M37 is another thousand light years beyond them. If any one of the clusters were as close as the Seven Sisters cluster in Taurus -- a mere 440 l.y. -- we'd see them easily with the naked eye.

From top to bottom: M36, M38 and M37.
as you'd see them in a telescope.
Beauties all. Photographed by Jim Misti

A small telescope will show them best but a pair of binoculars will reveal the trio as fuzzy spots mingled with stars. Since Auriga travels high across the sky from the northern hemisphere, haze and even light pollution aren't as big a problem in locating these three compared to finding a star cluster or nebula lower in the sky. When you gaze at these fuzzy spots, you're looking into the Milky Way's outer spiral arm, directly opposite the star-jammed galactic hub.

If binocular views of these starry M&Ms whet your appetite for more, later this week we'll look at how to spend some of that Christmas money on an easy-to-use, inexpensive telescope.

Posted by: rking@duluthnews.com on 1/5/2009 at 1:59 PM | Comments (0) | Permalink

Happy 5th Anniversary!

What the Mars rovers have accomplished under human guidance is nothing short of astonishing. Because of all we've learned and all the photos sent back, we no longer have to imagine what it's like to explore another planet. We're there. 
Now for more good news ---

From a NASA press release:

PASADENA, Calif. -- NASA rovers Spirit and Opportunity may still have big achievements ahead on the fifth anniversaries of their memorable landings on Mars.

Of the hundreds of engineers and scientists who cheered at NASA's Jet Propulsion Laboratory in Pasadena, Calif., on Jan. 3, 2004, when Spirit landed safely, and 21 days later when Opportunity followed suit, none predicted the team would still be operating both rovers in 2009.

This mosaic of frames from the rover Opportunity gives a view to the northeast from the rover's position on its 1,687th Martian day. Image credit: NASA/JPL-Caltech

The rovers have made important discoveries about wet and violent environments on ancient Mars. They also have returned a quarter-million images, driven more than 21 kilometers (13 miles), climbed a mountain, descended into craters, struggled with sand traps and aging hardware, survived dust storms, and relayed more than 36 gigabytes of data via NASA's Mars Odyssey orbiter.

Occasional cleaning of dust from the rovers' solar panels by Martian wind has provided unanticipated aid to the vehicles' longevity. However, it is unreliable aid. Spirit has not had a good cleaning for more than 18 months. Dust-coated solar panels barely provided enough power for Spirit to survive its third southern-hemisphere winter, which ended in December.

With Spirit's energy rising for spring and summer, the team plans to drive the rover to a pair of destinations about 200 yards south of the site where Spirit spent most of 2008. One is a mound that might yield support for an interpretation that a plateau Spirit has studied since 2006, called Home Plate, is a remnant of a once more-extensive sheet of explosive volcanic material. The other destination is a house-size, possible volcanic pit called Goddard.

For Opportunity, the next major destination is Endeavour Crater (pictured at right). It's approximately 14 miles in diameter, more than 20 times larger than another impact crater, Victoria, where Opportunity spent most of the past two years. Although Endeavour is about 7 miles from Victoria, it is considerably farther as the rover drives on a route evading major obstacles.

"The journeys have been motivated by science, but have led to something else important," said Steve Squyres, principle investigator for the rover science instruments. "This has turned into humanity's first overland expedition on another planet. When people look back on this period of Mars exploration decades from now, Spirit and Opportunity may be considered most significant not for the science they accomplished, but for the first time we truly went exploring across the surface of Mars."

Posted by: rking@duluthnews.com on 1/4/2009 at 10:52 PM | Comments (0) | Permalink

So familiar yet still mysterious

Isn't it odd that only one side of the moon is visible from Earth? Every night, every month, every year through the millenia, nothing but that good, old familiar face. You'll often hear references to the "dark side of the moon", a place some think is steeped in eternal darkness. "Farside" would be an accurate description, because the sun shines all over the lunar globe just as it touches every corner of the Earth. Because our planet rotates once in just 24 hours, we only have to wait a matter of hours for the return of day. The moon rotates once in 27 days. When the sun sets over a lunar location, an astronaut would have to wait almost two weeks for it to rise again. The upside is that once it rose, you'd get almost two full weeks of daylight.


The moon rotates on its axis in the direction of the red arrows. It turns at just the right rate to compensate for movement along its orbit (white circle). End result: observers on Earth always face toward the same side of the moon, represented by the blue figure standing on its surface. Illustrations: Bob King


If the moon didn't turn on its axis, over the course of its 27-day revolution around the Earth, we'd actually get to see all sides of it. The blue figure would face us at "A", appear off to one side at B, disappear around the backside at C and reappear on the right side at D.

Our intuition tells us that the moon mustn't be spinning if we can't see the farside. The truth is more subtle. We see only one side of the moon because it rotates on its axis once in the exact same time it takes to make one revolution around the Earth. Millions of years ago, the moon used to rotate more rapidly. Our distant, single-celled ancestors propelled themselves through the early oceans under an ever-changing moon. They knew no dark side.

Earth's more powerful gravitational pull has slowed the moon's spin since those days. The moon is now "tidally locked" to our planet, slowed to the point where the same hemisphere always faces moongazing Earthlings. Jupiter has played the same gravitational hand with its four brightest moons, Io, Europa, Ganymede and Callisto. The overwhelming gravity of Earth and Jupiter, compared to their moons, is like a sergeant commanding his recruits to stand at attention.

The moon is an outstretched fist to the left of the Great Square of Pegasus Sunday night (Jan. 4). The inset at lower left shows its phase. The map is drawn for 7 p.m. local time. Created with Stellarium.

Tonight the moon's 8-days-old, just past First Quarter phase. Using binoculars, this is one of the best times to discern the rough terrain -- and even a few craters -- along the terminator, the border between the brightly lit portion and the half still in shadow. You can also use the moon to guide you to the constellations of Pegasus and Andromeda. I'll be watching for the sparkle of moonlight on the seven inches of snow we received overnight. I wonder if the moonlight will be bright enough to show rainbow colors in the fresh crystals. Just gonna have to find out. 

Posted by: rking@duluthnews.com on 1/4/2009 at 1:11 PM | Comments (0) | Permalink

A minute a day keeps the blues away

Cover of the 2009 Farmer's Almanac. Photo: Bob King

I'm not a farmer but I love reading the Farmer's Almanac. It's been a faithful astronomical companion since I was a teen. Oh, I enjoy the stories about the best pickle making recipes just like anyone else, but I really sink my teeth into the 29-page calender section that lays out the sunrise and moonrise times for each day, along with a nifty summary of astronomical highlights for the month. Added to the mix are a few snippets of poetry and aphorisms like "A hungry stomach is beyond all logic" or "He that sows thistles shall reap prickles".

Looking at the almanac today, I notice two things. Sunset times are getting earlier by a minute a day. By month's end we'll have gained over a half hour of evening daylight. Sunrise is currently as late as it goes, and will remain that way until next Friday, when earlier sunrises begin peeling back the minutes.

Earth's elliptical orbit causes its distance from the sun to vary over a year's time. Tomorrow we'll be at perihelion, or closest to the sun. (not to scale) Click here for a table of perihelion and seasonal dates for the coming years. Illustration: Bob King

You may wonder why the latest sunrise doesn't occur on the first day of winter. Earth orbits on its axis as it revolves around the sun. As we complete a spin a day, the sun appears to rise and set. During early winter, we're closest to the sun and move faster than we do in July, when our planet is farthest from the sun. In January, we're moving fast enough that the planet has to rotate a little more to "bring up" the morning sun in order to compensate for our extra orbital speed.

That brings me to the second tidbit in the almanac. Tomorrow is perihelion (Pair-a-HEE-lee-un), when our planet is closest to the sun for the year. If Earth's orbit were a perfect circle centered on the sun, the distance wouldn't vary. But our orbit is an oval called an ellipse, with the sun just a little bit off to one side. Aphelion, or furthest distance, happens six months from now on July 4.

Despite being closer to the sun, January is typically winter's coldest month. What gives? It's important to remember that the main cause for the seasons is the tilt of the Earth's axis, which causes the sun to dip low in winter. The low slant of its rays and fewer hours of daylight are the reasons for winter's cold.Look at the diagram and you'll see that the difference in distance is only a few percent, not nearly enough to overpower the effect of our tilted axis.

Naturally, January is a summer month in the southern hemisphere. Do they have hotter summers because Earth is at perihelion? All the ocean waters in that part of the world tend to moderate any "perhelion effect" you'd expect. Now if Earth were at perihelion during northern hemisphere summers, there would be a difference, because there's more land north of the equator, and land heats up much faster than water.

The orbits of the inner planets. Green dots are perihelion positions, red dots are aphelion positions (furthest from the sun). Earth's orbit is nearly but not quite circular. Mars' is more stretched out, with a bigger difference between closest and furthest. Credit: Danial79

One planet where perihelion distance makes a difference is Mars. Although its axis is tilted almost identical to Earth's, Mars' orbit is more stretched out. Its distance from the sun varies from 149 million to 123 million miles. That's over 20%. With no water to mediate temperatures, both the winters and summers in the planet's southern hemisphere are much more extreme than in the north. Southern summers are up to 54 degrees warmer than those in the north.

The sun looks to return for our region on Monday. When it does, consider this nugget of wisdom from the almanac: "No matter how long the winter, spring is sure to follow".
 

Posted by: rking@duluthnews.com on 1/3/2009 at 11:40 AM | Comments (0) | Permalink

Hidden in plain sight

Venus is high in the afternoon sky in a photo taken on January 1. The planet was accompanied by the crescent moon and an airplane contrail. Credit: Andrew Kirk

With Venus so high in the sky this month, it's a tempting targe to spot it before sunset. I was surprised how bright the planet was during the most recent conjunction. Without even trying, I saw it 25 minutes before sunset -- a pearl in the blue sky. Andrew Kirk of Bishop, California picked it up in early afternoon on New Year's Day. "I saw Venus shortly after 1 p.m., naked eye. I still can't believe it!" said Kirk.

Naturally, it's easier to find the planet with the nearby moon as guide, but you can use whatever's handy to help. On the next clear night, go out as early as you can -- just a few minutes past sunset is good -- and line Venus up with a tree, rooftop, distant hill, or even a streetlight. Make a mental note of where you're standing when you do this. The next time it's clear, go out a half-hour earlier and look to the left or east of that line to spot the planet. If you look at Venus often, you'll get a good feel for where it's at and how it moves across the sky. This will help you find it earlier and earlier.

Don't worry if your neighbors mistake your skyward squinting for end-of-days gazing. Just explain you have a rendezvous with the goddess of love and beauty. On second thought ...

Posted by: rking@duluthnews.com on 1/2/2009 at 7:51 PM | Comments (3) | Permalink

Quads of fun

"Bundle up and keep moving," was mailman Don McMillin's advice for surviving this morning's cold. Behind him, "steam" rises from Lake Superior as cold air condenses into clouds over the water. Photo: Bob King / Duluth News Tribune

Below zero and a killer wind this morning. I took this photo on the way in to work of mailman Don McMillin crossing the street. Lake Superior in the background. You see those wisps of fog? We call it 'steam' around here, and it's common over the lake on cold mornings until ice-over. Cold air blowing in from the northwest passes over the warmer lake, chills out and condenses into vapory wisps. Much the same happens when you see your breath on cold days.


Wispy clouds rise over the flank of Olympus Mons, Mars'
tallest volcano, which stands 16.7 miles high. That's three
times higher than Mt. Everest. Credit: NASA/JPL/MSSS

This process is also a familiar one on Mars. Even though Mars' atmosphere has scant water vapor, there's enough to form clouds if the conditions are right. When warmer air containing water vapor rises up the slopes of the Olympus Mons volcano, it cools and condenses just like the fog over Lake Superior, creating a cloud deck of ice crystals. It might as well have been Mars here in Duluth this morning. The cold made me shudder.


Tomorrow morning the sky will shoot Quadrantid meteors. They'll appear to radiate from a spot below the Big Dipper and across from Arcturus. The best time is between 2 a.m. and dawn. The closer to dawn, the more meteors you'll see. Created with Stellarium.

Early Saturday morning (Jan. 3), the sky will be host to the first meteor shower of 2009, the Quadrantids (KWA-dran-tids). The name recalls the obsolete constellation Quadrans Muralis, depicted on some 19th century star atlases. It was created from unassigned stars in Bootes, Hercules and Draco. Quadrans Muralis was declared extinct by the International Astronomical Union in 1922, but the the name stuck to the meteor shower that radiates from the area every January.

The peak time for viewing will be just before dawn tomorrow morning. The fast-moving meteors will arrive at a rate of 60-100 per hour from a radiant point just below the Handle of the Big Dipper. Although a good show is forecast for the central and western U.S., a snow storm threatens our chances here in Duluth. Unlike most other meteor showers, the Quadrantids have a very sharp peak (maximum meteor rate) only a few hours long. The very best display will occur over the western U.S. No moonlight will interfere.


Jeremie Vaubaillon, Caltech, created this composite image of the 2008
Quadrantid shower combining short exposures of meteors and aurora seen
during the returning leg of the Quadrantid aerial study.

Several years ago, I got up to watch the shower, and was impressed not only with how many I could see, but how bright they were. When the timing is right, as it is this year, the Quadrantids are impressive. I hope you have clear skies, and if so, let us know what you see.

I've written before that most meteor showers are spawned by debris left by passing comets. The Geminids and Quadrantids are a little different. Their origins trace back to rocky asteroids. 2003EH1 is the parent of tomorrow's shower. It was likely part of a shattered comet that has since fizzled away to bare rock.

(The animation, at right, shows 1.2 mile-diameter asteroid 2003EH1 moving through a starfield. The asteroid is the small dot crossing through the center of the picture. Credit: ESO)

Posted by: rking@duluthnews.com on 1/2/2009 at 11:55 AM | Comments (0) | Permalink

An extra helping of astronomy

Galileo's first looks at the sky with his homemade telescope in 1609 helped inspire this years' IYA 2009. Some of his original drawings include (clockwise from left): Saturn and sunspots, the moon in different phases, Jupiter and its moons and the Seven Sisters star cluster. 
 
Welcome to the new year! 2009 is a special one for our shared interest. It's the International Year of Astronomy 2009 (IYA 2009), a yearlong celebration of astronomy marking the 400th anniversary of Galileo's first astronomical observations with a telescope, and Johannes Kepler's publication of the laws of planetary motion in Astronomia Nova.

The International Astronomical Union and UNESCO are coodinating the worldwide celebration and educational outreach. IYA 2009 hopes to bring astronomy to as many of Earth's 6.8 billion residents as possible. The goal is simple yet profound: increase awareness of the incredible universe around us. Plans call for collaboration between professional and amateur astronomers, outreach both online and in the classroom, and special planetarium and astronomy club programs across the world.

One of the projects is called The Galileoscope: Millons of People Eyeing the Sky. Every participant in an IYA2009 event can buy an easy-to-assemble kit to build a telescope similar to Galileo's for just $10. Then there's the Cosmic Diary: The Life of an Astronomer, where professional astronomers will blog about what it's like to be a working astronomer. Their writings and photos will become the basis of a book to be published later this year.

Never had the pleasure of looking through a telescope? IYA 2009 hopes to change that in 100 Hours of Astronomy on April 2-5, with public observing events and live webcasts from professional observatories coordinated across the globe. Our local club, the Arrowhead Astronomical Society, will be out in force serving up slices of the universe those nights. We hope to see you then.

Dark sky awareness, promotion of gender equity in the sciences, free online astronomy courses, and programs to introduce children in underprivileged countries to the wonders of the sky -- the list goes on and on. If you're a teacher, you'll have the opportunity to engage your students in the astronomical excitement through the Galileo Teacher Training Program , a complete online resource of astronomy-education content.

In the coming weeks, I'll update this blog with websites and event schedules. More information and descriptive links can be found here.

Posted by: rking@duluthnews.com on 1/1/2009 at 12:36 PM | Comments (0) | Permalink

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