700 billion is a lotta stars
$700 billion dollars. We all know what that number means. It's a figure that can truly be called astronomical. How might we come to understand how large a number 700 billion really is? The answer's simple: think astronomically.
700 billion dollar bills, arranged end to end, would reach from Venus to the sun. Illustration: Bob King
Let's start with distance. A one-dollar bill is six inches long. Mulitiply that measure by 700 billion and you get 66,287,879 miles. If you taped each bill end-to-end, they would span the distance between Venus and the sun. Whew, that's quite a paper trail. 700 billion dollar bills could also be wrapped around the circumference of the Earth 2,651 times.
An artist's view of the Milky Way (left), based on the latest scientific data, and a photograph of the Andromeda galaxy. Both are large spiral galaxies with a combined number of stars upwards of 400 billion. Credit: NASA/JPL-Caltech (left) and John Lanoue
Distances bore you? Let's try objects. There are roughly 200 billion stars in the Milky Way galaxy, and a similar number in the Andromeda galaxy, the nearest large galaxy. Even if you gave one dollar to every star in both galaxies, you'd still have plenty left over to pass out to all the stars in the small galaxies neighboring the Milky Way. What to do with the last million or two in pocket change? Make a donation, treat yourself to a new car, invest and of course, buy that shiny new telescope.
There's nothing like the sky to put things in perspective ...
(Special note: You've got to check out this video of the ATV cargo ship breakup on the European Space Agency website. What a fireball!)
Posted by: rking@duluthnews.com on 9/30/2008 at 11:19 AM | Comments (0) | Permalink
Drop in anytime
The world in a drop of water. Close inspection of water drops on a twig in my neighborhood this morning reveal multiple images of lawn, trees and landscape. I flipped the image so you could better inspect the details. Each drop acts as a lens that focuses the scene in the background. Photo by Bob King / Duluth News Tribune
Everthing dripped with rain and dew this morning, inviting exploration of the world of water with eye and camera. Water droplets were probably the very first lenses. A small, nearly spherical droplet held together by its own surface tension can magnify 2x or more. By the 8th century (maybe earlier), "reading stones" of polished quartz and other minerals were used to magnify text. These resembled the cylinder or bar-shaped magnifiers we still use today. Spectacles appeared in the 1280s, and by the 1600s folks like Galileo and Anton van Leeuwenhoek, builder of early microscopes, created lenses of such quality that they became powerful tools of discovery.
Instructions for building your own water-lens magnifier can be found here. And if you're curious about how lenses work, you can learn more at this site.
The ATV, otherwise known as Jules Verne, burns up in a raging fireball over the Pacific Ocean earlier today. More information here. Photo: ESA
While you were eating breakfast this morning around 8:30 Central time, the ATV (Automated Transfer Vehicle) became a flaming meteor as it burned up in the atmosphere over an uninhabited area in the South Pacific Ocean. It was seen by aircraft and space station astronauts. Here's the full report. The cargo ships's six-month mission was a great success. Additional ATVs will be launched at six-month internals to dock with the space station and deliver equipment and supplies.
You can use this map to get you to Neptune's vicinity. It shows the sky as you face south around 8:30-9 p.m. Start with Jupiter and Altair, the bottom apex of the Summer Triangle. Use them to guide you to the pair of stars called Alpha and Beta in Capricornus. Once you've found these two, look two fists to the left (east) to Delta, and then use the close-up map below. -- created with Stellarium
Focus your binoculars now on Delta and slowly move them upward until you spot the "index finger". Got it? Good. Now move to the right and pick off star 1 and star 2. The "star" above star 2 is Neptune. Congratulations! -- created with Chris Marriott's Skymap Pro at skymap.com
The extended forecast shows several nights with clear skies this week, a fine time to return to Neptune. Several weeks ago, I posted a map on how to find this remote planet that most of us never get to see. Surprisingly, it's visible in a pair of 7x50 or 10x50 (or larger binoculars) from suburban and rural locations. Since then, the planet's moved a smidge to the west so I refreshed the map. You can use the wide map to put you on the path to Neptune. The second, more detailed view should help you nail it. Find a place with reasonably dark skies to the south. Two nights ago I put the maps to the test and found the planet without too much trouble in my 10x50s. Let us know if you find it too.
Posted by: rking@duluthnews.com on 9/29/2008 at 8:54 AM | Comments (0) | Permalink
Return of the unfortunate dragon
I helped my younger daughter identify a collection of insects last night, including a little jewel of a leaf beetle that looked like it had been dipped in silver paint. This was a particularly big accomplishment for us since beetles are one of the most successful insect groups in the world, boasting something like a million and half species.
After the bugs, we watched the Saturday Night Live intro and comic debate. During commercials, I stepped outside and found the sky spanking clear with stars so bright, it looked like a cleaning crew had come through. The time was late. Already autumn stars like the Square of Pegasus stood high in the south, while winter constellations like Taurus the Bull and even Orion bullied their way up in the east.
Draco is a dim but distinctly-shaped constellation well placed for early evening viewing in early fall. This map shows the sky as you'd see it while facing north around 8:30 p.m. The Dragon is a sinuous path of stars that starts just above the Bowl of the Dipper and ends right below brilliant Vega, high in the west. The Head of the Dragon is nicknamed the "Lozenge" because of its cough-drop shape. -- created with Stellarium
Draco the Dragon, like Ursa Major (Big Dipper), is a constellation that overlaps several seasons. We first visited Draco in a blog last spring when its flaming snout cleared the eastern horizon in May. We return again in the fall to see it conveniently placed for early evening viewing. Draco remains a perennial favorite of children at planetarium shows because it's one of the "scary" constellations like the Scorpion or the Sea Monster Cetus.
The constellations figures are superimposed on Ursa Major,
the Great Bear, Draco and Hercules. -- created with Stellarium
Now that the sky is dark before children are in bed, it's really an ideal time to go out and find the dragon together with them. Find a place with a reasonably open northern sky, and let your eyes adjust to the darkness. The first star above the end of the Dipper's Bowl is the tip of his tail. Connect the dots upward toward Vega, which is nearly overhead at that hour. There are no bright stars in Draco but the Lozenge should be the easiest part to see.
As long as you're out tonight, you can watch for a great pass of the International Space Station (ISS) starting at 7:45 p.m. Central time (Sept. 28). It'll cut a path right through the Big Dipper's Bowl as it crosses the northern sky. Five minutes later at 7:50 p.m,, the Jules Verne cargo ship (ATV) makes its last good pass for us before it's de-orbited tomorrow and burns up in the atmosphere over the South Pacific Ocean. Its track will nearly match that of the ISS.
Draco was slain by the Strongman Hercules, as one of the 12 labors he was given to redeem himself after killing his family in a fit of insanity, induced by the goddess Hera. Talk about playing hardball. Hercules completed them all and became the greatest of Greek heros. Both he and Draco are remembered in the stars we see tonight.
Posted by: rking@duluthnews.com on 9/28/2008 at 10:30 AM | Comments (0) | Permalink
Appointment with the goddess
Well, I can tell you this. Lightning and heavy rain last night sure made it hard to see the Shenzhou spacecraft pass. Think of how serene things must have been for the three astronauts sailing 200 miles overhead through the quietude of space. Had they paid any attention to little us, they would have seen tiny flashes of light from a black corner of the globe. That's all.
To see a video of China's first spacewalk, click here. I think you'll enjoy how astronaut Zhai Zhigang waves for the camera as the Earth rolls in the background. Depending on exactly when the spacecraft returns to Earth, we may get another shot at seeing a pass on Sunday. Meanwhile, the International Space Station will make a low pass in the northwestern sky tonight (Saturday) beginning at 8:55 p.m. Then at 9:07 p.m., watch for the Jules Verne module (ATV) to appear briefly below the Handle of the Big Dipper. In two more days, it'll be toast when re-enters Earth's atmosphere over the Pacific.
The planet Venus, goddess of beauty and love, still hugs the western horizon over the coming weeks but it's getting a little easier to see every night. This map shows the sky around 7:20-30 p.m. looking west-southwest. -- created with Stellarium
The sky is always bountiful. Tonight you can find Venus low in the west starting about 20-30 minutes after sunset or about 7:20 p.m. Look for a brilliant "star" about three outstretched fists to the left of the bright sunset point.
Because Venus circles the sun inside Earth's orbit, it changes phase and size from our perspective. We watch the planet wane from full to crescent as it approaches the Earth in the evening sky (left half of diagram). After passing us, Venus appears in the morning sky (right half), and goes through its phases in reverse. Venus is closest to Earth and appears largest when it's a crescent. Illustration: Ville Koistinen (with my own additions)
Just like our moon, Venus changes its phase. In a telescope tonight, it'll look like a little gibbous moon, just shy of full. Venus speeds around the sun in a 225-day orbit. As it does, the planet changes both phase and apparent size as it approaches and then passes the slower Earth. It's a lot of fun to watch these changes through a small telescope. Crescent looks the coolest because it's so delicate and large. Even binoculars will show it. We'll keep tabs on Venus in the coming months as the goddess ascends the evening sky.
Andrew Kirk of Bishop, California was out with his camera again, and sent me several beautiful photos yesterday. I thought you might enjoy seeing them. Thanks Andrew for sharing these with our readers!
The crescent moon huddles among a sumptuous display of crepuscular rays in this photo taken on Friday morning, Sept. 26. Photo credit: Andrew Kirk
Crespuscular rays burst the seams of this massive cumulus cloud on September 17. To create the super wide-angle view, Andrew used a program to stitch four separate, adjacent images into one. Photo credit: Andrew Kirk
Posted by: rking@duluthnews.com on 9/27/2008 at 10:20 AM | Comments (0) | Permalink
Worlds in collision
The rocket stage that propelled Shenzhou into orbit passes just below Jupiter in this photo taken last night (Sept. 25) at 8:09 p.m. The sky's pink cast is caused by light pollution from the city of Duluth. Details: 70mm lens at f/2.8, 30-second time exposure at ISO 800. Photo: Bob King / Duluth News Tribune
Tonight may be the only night we get a good shot at seeing the Shenzhou-7 spacecraft carrying the three Chinese astronauts. Their mission lasts three days, and Saturday night's overflight of our region happens too early in the evening to see well. The forecast doesn't look particularly promising but my Clear Sky Chart shows a clear to partly-cloudy break from 7 to 9 p.m., exactly during the observing window. I'll be out, and hope you will too.
The map shows the path of the Shenzhou-7 spacecraft tonight (Sept. 26) as it travels from right to left across the southern sky. By good fortune, the ship will pass very near Jupiter -- and be at its brightest when it does -- before entering Earth's shadow and fading out. -- created with Stellarium
Go out a few minutes before the pass to get your eyes accustomed to the dark. The ship will be rather faint, so a pair of binoculars will be helpful to spot it. Don't forget that at 8:28 p.m. the much brighter International Space Station will appear in the northwest and climb into the sky near the Big Dipper. It's a good warm-up for Shenzhou-7.
Two hypothetical Earth-like planets in orbit around the double star BD+20 307 collide to form a fresh ring of dust around the suns. Illustration by Lynette Cook and used by permission.
In other astro news this week, astronomers have discovered an extraordinary amount of dust ringing a pair of older, sunlike stars called BD+20 307 some 300 light years away in the constellation of Aries. Dust rings and envelopes are relatively common around young stars in the process of forming planets. As stars mature, the dust either dissipates or is incorporated into the new planets. Old stars shouldn't have tons of dust around them, which is why astronomers are convinced that it was created by the collision of two Earth-sized planets. One or both of them strayed from their stable orbits and toward a collision course with the other.
Chances are small that something so catastophic could happen, but during the lifetime of our own solar system, scientists predict a possible collision of Mercury with Earth or Venus in the next billion years or so. Our very moon was likely formed as a result of a collision between a Mars-sized planet and the Earth in the early days of the solar system.
Things appear safe and stable at home base for now, but add the element of time, and tiny probabilities can add up to powerful realities.
Posted by: rking@duluthnews.com on 9/26/2008 at 10:07 AM | Comments (1) | Permalink
Kung-pao chicken to go
A maple tree lifts its crown to last night's clear, starry sky.
The cloudy streak with a bright center at top is the Andromeda
galaxy. Photo: Bob King / Duluth News Tribune
Update 10:35 p.m. -- see map below for tonight's pass of Shenzhou-7
Sweet night yesterday if only for a little while. We had clouds but not before two bright space station passes and one flyover of our friend, Jules Verne (ATV). With a little luck in the weather department, we'll be treated to evening passes of a brand new satellite, the Chinese manned spaceship Shenzhou-7. The name means "Divine Vessel" and the ship will carry three Chinese astronauts -- called taikonauts -- into orbit for a three-day journey into space. Tomorrow, one of the astronauts will perform China's first spacewalk, the mission's highlight.
Chinese astronauts (left to right), Jing Haipeng, Zhai Zhigang and Liu Boming attend a send-off ceremony before the launch of China's third manned space mission at the Jiuquan Satellite Launch Center in Gansu province on Thursday, Sept. 25. (AP PHOTO)
The ship launched at 6:10 Central time this morning the 25th with great fanfare. On board, the taikonauts will get to choose from a menu of 80 different foods including spicy kung-pao chicken, shrimp and dried fruits. They'll also use special pencils costing $1470 from a firm in Shanghai to take notes on what they observe in space. The pencils are three times the thickness of regular pencils, made of slip-proof basswood and can be used on both ends. China First Pencil Co. Ltd. will produce an additional 2,008 pencils for general sale at $750 a pop. Sounds like American-style capitalism is alive and well in China.
It's a great achievement to send humans into space, and the Chinese are justifiably proud. China's growing space program can only enhance our understanding of the world that begins where our atmosphere ends.
As soon as predictions for evening flyovers are available, I'll update the blog on when and where to look for Shenzhou-7, so check back later in the day. I hope we'll all get a chance to see this historic flight. For more information on the mission, you can click here. For a fascinating look into the origin of (ahem) pencils, take a look at this story.
At right, a Long-March II-F rocket blasts the three Chinese astronauts into Earth orbit early this morning. (AP PHOTO)
The path of Shenzhou-7 through Northland skies this evening the 25th. We may also get to see the final rocket stage precede the spacecraft, so watch for two lights to pass across brilliant Jupiter. Shenzhou-7 will be faint this evening so I'd recommend binoculars to catch it. Look left and right of Jupiter at the times shown. After 8:10:45 p.m., the craft will disappear into Earth's shadow. We'll have it nailed down much better for the Friday and Saturday passes. You may also want to start viewing a couple minutes early and stick around for a couple minutes after the times on the map. Good luck!
Update 10:35 p.m. -- Yes, it was visible! Based on a communication with a satellite prediction expert, it was the spacecraft's rocket stage that followed the track pictured above, and it appeared about a half-minute early. You wouldn't call it bright, but it was still easily visible to the naked eye. It moved quickly and faded out just to the left (east) of Jupiter. I hope you saw it. The ship itself passed a few degrees above Jupiter about five minutes later but I did not see it. Please share your observation by leaving a comment below.
Tomorrow's blog will have the remaining passes listed.
Posted by: rking@duluthnews.com on 9/25/2008 at 9:18 AM | Comments (0) | Permalink
Einstein and the Dumbbell
Nice to wake up to the sun shine this morning. The haze of the past week was swept away so completely that the waning crescent moon stood out sharply in the clean sky even at 9 o'clock. The Clear Sky Chart for our region forecasts cloudless skies through the early hours of tomorrow morning. This will give us a great chance to see lots of satellites (see yesterday's blog) and find the Dumbbell Nebula. More about that in a minute.
On Monday, an unidentified man adjusts a telescope that once belonged to Albert Einstein. Students and visitors will be able to look through the long-lost scope starting Thursday after it's renovated. (AP Photo/Hebrew University in Jerusalem)
I read in today's paper about the discovery of Einstein's long-lost telescope. It was stored in a shed at Hebrew University in Jerusalem. Einstein received the scope in 1954, the year before he died, as a gift from his friend Zvi Gizeri. Gizeri likely made the scope himself. It's clearly a reflecting telescope -- one that uses mirrors to gather and focus light -- on a heavy-duty metal mount. Since the tube measures about eight inches in diameter and six feet long, the mirror would be six to eight inches across. This would have been a substantial amateur telescope for the era.
You wonder if Einstein actually used it to look at the sky. If he toted the scope into his front yard on September 24, 1954, he would have seen Mars almost exactly where Jupiter is now in Sagittarius. More likely, he pondered equations deep into the night, trying to reconcile quantum mechanics with relativity. Let's assume he stepped out into the pre-dawn air to clear his head. If Einstein looked to the east, Jupiter in Gemini would have caught his gaze for sure. We'll probably never know for certain if he hauled it outside for a look-see, but it's cool just to know that Einstein had a telescope.
This map shows the southern sky around 9 o'clock this week. You'll recall that Vega, Deneb and Altair form the familiar asterism of the Summer Triangle. Altair is due south and halfway up in the sky. The Dumbbell's home is the faint constellation of Vulpecula the Fox. To find the nebula, you can use Sagitta the Arrow, located one outstretched fist above Altair. -- created with Stellarium
You won't need a telescope to see the Dumbbell Nebula, which is located just above the little, arrow-shaped constellation of Sagitta the Arrow this fall. Binoculars will do. The Dumbbell was the first planetary nebula to be discovered. It was snagged in telescopic sweeps by that famous seeker of comets, Charles Messier, in 1764. Planetary nebulas are small, round clouds of glowing gas whose distinct shapes reminded early astronomers of planets, hence the name.
At the center of each planetary is a faint, tiny and impossibly dense star called a white dwarf. One teaspoon of white dwarf matter weighs five tons. Or how about this: A white dwarf packs an entire sun's worth of matter into a sphere the size of Earth. They're the ultimate tin of sardines.
The Dumbbell Nebula, also known as M27 (the 27th entry in Messier's catalog of deep sky objects) shines by the light of the white dwarf star visible at its center. The Dumbbell is around 1300 light years from Earth. This time-exposure photo reveals the green glow of excited oxygen atoms in rarified gas. Photo: Jim Misti
The sun will evolve into a white dwarf as it ages and ultimately runs out of nuclear fuel. Some four to five billion years from now, our favorite star will shed its atmosphere, exposing its very core. The intense ultraviolet radiation from the core, now called a white dwarf star, will excite the expanding shell of its former atmosphere and create a beautiful, glowing sphere. Voila! A planetary nebula. Their lovely oval and round shapes and cool blue-green colors place planetaries high on the "favorites" list of amateur astronomers.
The Dumbbell gets its name from the familiar hand weight form, which shows very nicely in a telescope. The nebula is also easily seen in ordinary binoculars as a fuzzy, cloud-like patch some three "fingers" above the end of the Sagitta arrow. Point your binoculars right above Altair, and find the line of stars that make the arrow. The nebula is directly above the arrow tip. Matter of fact, if you put the "tip star" in the bottom of your binocular field, you'll probably see the Dumbbell in the top half.
Binocular star gazing is more challenging than naked eye but when mastered, you'll be on a first-name basis with more members of the cosmic zoo than you ever realized were there.
Posted by: rking@duluthnews.com on 9/24/2008 at 9:55 AM | Comments (0) | Permalink
Welcome to the family
The newly-named dwarf planet Haumea and its two moons, Hi'iaka (bottom) and Namaka, were discovered by astronomer Mike Brown on December 28, 2004. He gave Haumea the nickname "Santa" at the time. Last week, it received its official name and classification as a dwarf planet. Illustration: NASA
Last week astronomers added another dwarf planet to our solar system. Named Haumea (how-MAY-eh), after the Hawaiian goddess of childbirth and fertility, it joins a select group that includes Ceres, Pluto, Makemake (mah-kee-MAH-kee) and Eris. 
Dwarf planets are large enough to be nearly spherical but not big enough to keep their orbital neighborhoods clear of other asteroids and the like. Haumea, discovered by Mike Brown (right), professor of planetary astronomy at the California Institute of Technology, stretches the definition of round. It's shaped like an egg with dimensions of 1200 by 600 miles, and rotates once every four hours. Two tiny moons -- Hi'iaka and Namaka -- named after Haumea's daughters, accompany the dwarf planet as it orbits the sun at the chilling distance of four billion miles. That's a billion miles beyond Neptune, the furthest planet. If you could walk on Haumea, you'd feel the crunch of an unusual form of crystalline ice under your boots. An odd little world indeed.
Over a thousand minor solar system bodies, including four dwarf planets, have been discovered beyond Neptune. Here's a sampling of the biggest ones. Notice that Eris is larger than Pluto. Illustration: NASA
Last night the sky was perfect for seeing the brilliant pass of the International Space Station after 8 o'clock. It was preceded by a fine pass of the ATV (Automated Transfer Vehicle) that serviced the station earlier this year.
In this 60-second time exposure photo, the International Space Station passes beneath the bright star Vega (upper right) last night, Sept. 22, about 8:20 p.m. Photo: Bob King / Duluth News Tribune
The following tables show the times of additional good passes this week of the ISS, the ATV and a rather peculiar satellite, the Early Ammonia Servicer (EAS) (below). 
The EAS is 1400-lb. unneeded piece of coolant equipment the size of a big refrigerator. It was jettisoned from the ISS last July and will burn up in Earth's atmosphere sometime next spring. I've never seen this new satellite but according to the predictions, it will make some passes this week over our region. It's not bright. Look for a moving light a little fainter than the stars in the Big Dipper at the appointed times. I wish you success!
Internation Space Station passes:
| Date | Time to look | ISS path in sky | Maximum altitude |
| Tuesday, Sept. 23 | 8:43 p.m. | from west to n.east | five fists (bright) |
| Weds., Sept. 24 | 7:34 p.m. | from wsw to east | overhead (brilliant!) |
| Weds., Sept. 24 | 9:10 p.m. | from wnw to north | three fists |
| Thurs., Sept. 25 | 8:01 p.m. | from west to n.east | four fists (bright) |
ATV passes:
| Date | Time to look | ATV path in sky | Maximum altitude |
| Tuesday, Sept. 23 | 8:14 p.m. | from wsw to n.east | six fists (bright!) |
| Weds., Sept. 24 | 8:27 p.m. | from west to n.east | four fists (bright) |
| Thurs., Sept. 25 | 8:39 p.m. | wnw to north | three fists |
| Friday, Sept. 26 | 8:51 p.m. | northwest | three fists |
Early Ammonia Servicer (EAS) passes:
| Date | Time to look | EAS path in sky | Maximum altitude |
| Tuesday, Sept. 23 | 8:30 p.m. | n.west to n.east | three fists |
| Weds., Sept. 24 | 8:23 p.m. | n.west to n.east | four fists |
| Thurs., Sept. 25 | 8:15 p.m. | n.west to n.east | six fists (good pass!) |
| Friday, Sept. 26 | 8:07 p.m. | n.west to s.east | overhead (best!) |
| Saturday, Sept. 27 | 8 p.m. | n.west to s.east | six fists (very good) |
Posted by: rking@duluthnews.com on 9/23/2008 at 9:48 AM | Comments (0) | Permalink
Everything falls into place today
Gorgeous orange mushrooms only an inch tall sprouted recently in my front yard. The longer nights and rains that are part of the fall season are ideal for mushroom growth. Photo: Bob King / Duluth News Tribune
Even as I write this, the last minutes of summer are ticking by as we prepare to set foot into autumn. At 10:44 Central time this morning the 22nd, the sun will cross the celestial equator on its journey southward. The celestial equator is simply a projection of the Earth's equator onto the sky above. For residents of equatorial cities like Padang, Indonesia and Quito, Ecuador, the sun rose due east this morning, will pass directly overhead at noon and set due west. Because Duluth is some 47 degrees north of the equator, the projection of the equator in our sky is 43 degrees high or about four outstretched fists above the southern horizon.
From mid-northern latitudes like Duluth, the sun still rises due east and sets due west, but its maximum height above the horizon around noon is about 45 degrees or halfway between the zenith (top of sky) and southern horizon. 
At the north pole, the celestial equator sits directly on the horizon. If you could stand there today, you'd see only the top of the sun on the horizon describe a complete circle around you in 24 hours. In a few days, the sun will disappear below the horizon for north pole dwellers, marking the start of six months of twilight and night. The image at right, of the north pole icescape, was taken by a webcam operated by NOAA and the Pacific Marine Environmental Laboratory. To see more, click here.
Good thing we're south of the pole. Things won't be nearly so bleak here. The first day of fall is also called the autumnal equinox. The root "equi" refers to the equality of day and night. Both are about 12 hours long today.
The sun set nearly due west in this photo taken by Connie in northern Minnesota on September 20. On the first day of fall, the sun shines directly over Earth's equator.
We're at the balance point on our seasonal see-saw today. During the first half of the year, our end slowly rose upward while our southern hemisphere counterparts' seat descended. Today we sit directly across from one another -- Australians are enjoying the first day of spring as we begin the fall. When our feet finally touch the ground three months from now, we'd better be wearing boots because winter will be at hand.
Special update:
There's going to be an spectacular pass of the International Space Station tonight (Mon. Sept. 22) during the early evening. Watch for it to appear in the west-southwest at 8:17 p.m. and cross nearly overhead at 8:20 p.m. It will rival Jupiter in brightness. Tomorrow I'll post more times not only for the ISS but also the ATV and a new (and curious) satellite.
Posted by: rking@duluthnews.com on 9/22/2008 at 10:08 AM | Comments (0) | Permalink
Double your cluster pleasure
This map shows the northern sky around 8:30 p.m. the first week of fall. Cassiopeia is the bright W of stars well-placed halfway up in the northeastern sky. -- created with Stellarium
The moon's at last or third quarter phase, having completed 3/4 of its monthly orbit around the Earth. It has the same "half a pie" shape like the first quarter moon but reversed, with the left half lit. The moon still provides enough illumination for distinguishing forms in the night landscape but clearly its light is slipping away. Dark skies are again at hand.
With the stars back in full force and Cassiopeia the Queen in her glory, this coming week will be a good one to find the Perseus Double Cluster. Even though it's in the constellation of Perseus the Hero, the Double Cluster is found more easily using Cassiopeia's stars. Just drop one outstretched fist below the left side of the W and look for a small, puffy cloud. If you can see the Milky Way in Cassiopeia, the Double Cluster will look like a brighter condensation within it. It's not hard to spot from suburban neighborhoods. The ancient Babylonians and Greeks knew this little cloud too. The Greek astronomer Hipparchus included it in his catalog of the sky in 130 B.C.
The Double Cluster is directly below Cassiopeia and one of the sky's best binocular objects. You can also use the W to point you to the Andromeda Galaxy, described in an earlier blog. Photo: Bob King / Duluth News Tribune
To the naked eye, there's not much more to look at than an unresolved glow about the size of two full moons, but binoculars reveal the cloud as a splendid pairing of two individual star clusters. With my favorite pair of 10x50s, I can resolve lots of stars in each cluster and enjoy their different characters. The cluster on the left is called NGC 884, its companion to the right is NGC 869. 869 is richer in stars and more compact than its neighbor. Both clusters are some 300 light years apart and approximately 7000 light years from Earth.
This photograph of the Double Cluster gives you a good idea how it appears in an amateur telescope. NGC 884 is at left , and NGC 869, right. Notice the red stars, especially around 884. Photo: N.A. Sharp, NOAO, AURA, NSF
We've seen that some pairings in the sky are chance alignments but that's not so with Double Cluster. Both of them are anchored together in an enormous cloud of gas and young stars called the Perseus OB1 association, located in an outer spiral arm of our galaxy. If you sweep the sky around the Double Cluster with binoculars, I guarantee you'll bump into even more clusters.
I'll never forget my first look at the Double Cluster as a boy from my suburban Chicago neighborhood. Even there, I was knocked over by the hundreds of stars I could see in my low power telescope. Several ruby-red stars sprinkled about added an additional dimension of beauty to the scene. A little horseshoe of stars at the center of 869 is one of my favorite asterisms in the sky.
All star clusters are gravitationally-bound collections of stars born from clouds of gas of dust called nebulas. Astronomically speaking, both of our featured clusters were born recently: six million years ago for NGC 869 and 14 million for NGC 884. For comparison, consider that the sun is five billion years old. The Double Cluster is filled with freshly-minted supergiant and giant stars that shine with a fierce brilliance. They're a highlight of the new season now at hand.
Posted by: rking@duluthnews.com on 9/21/2008 at 9:34 AM | Comments (0) | Permalink
Now that's a bear of a different color
A deer crosses Riley Road in Lakewood Township shortly before sunset last night (Sept. 19). Thick haze tinted the sun cherry-red. Photo: Bob King / Duluth News Tribune
We had a lot of haze last night, and I never did see the ATV during its brief pass. Anyone catch it? Otherwise the night was unusually warm. During twilight I even saw one or two male fireflies dipping over the tall grass apparently in search of a female. It's unusual to see fireflies this late in the season. Fall starts Monday.
It's not too hard to see a bear among the stars of Ursa Major if you have an open view to the north-northwest. Look about halfway up in the northwestern sky around 8:30 p.m. to find the Dipper. Connect the dots to extend the Dipper -- the bear's back and tail -- to the fainter stars that form his legs and head. -- created with Stellarium
This is a good time of year to see the full outline of the constellation Ursa Major, the Great Bear. Just about all of us can recognize the Big Dipper. It's currently positioned at a comfortable viewing angle in the northwestern sky around 8:30 p.m. The bear's paws are tip-toeing over the treetops this time of year.
The seven Iroquois hunters pursue the bear across the early fall sky. The star that represents Owl is more familiar to us as Arcturus, the brightest star in Bootes the Herdsman. Can you find all seven hunters the next clear night? The cooking pot is the star Alcor, the closeby companion of Mizar. -- created with Stellarium and based on historical information from J. Staal's The New Patterns in the Sky. More Native American sky myths can be found here.
The Iroquois Indians of early America saw the bear differently that we do. To them, the four stars of the Bowl represented the entire bear, while the Handle stars and several stars of the constellation Bootes were the seven hunters. The hunt begins in the spring but by the time autumn arrives, the four furthest hunters have set in the west, leaving only Moose Bird, Chickadee and Robin. Robin finally succeeds in killing the bear with an arrow, and when the animal rises up in a final shaking before falling to its death, it sprays blood onto the forest, coloring the leaves red.
The bear is prepared and eaten using the cooking pot carried by Chickadee. All that's left during the winter months is the bear's skeleton. Come spring, a new bear emerges from the den and the hunt begins again. This story is a wonderful way of looking at the familiar cycle of birth, death and rebirth that is so much a part of the changing seasons as well as our own personal lives.
Towering cumulus clouds glow pink before sunset last night (Sept. 19) Photo: Bob King / Duluth News Tribune
Posted by: rking@duluthnews.com on 9/20/2008 at 9:20 AM | Comments (2) | Permalink
See it before it bursts into flames
The sawtooth border of a cottonwood leaf, yellow with the approaching season, glows in the sunlight this morning. Photo: Bob King / Duluth News Tribune
We're going to have some fun things to look at tonight. The International Space Station (ISS) is once again making bright passes in the evening sky, and along with it, the Automated Transfer Vehicle (ATV). You might recall that the ATV, better known as Jules Verne, ferried food, clothes, water and more to the astronauts aboard the station last spring. It has since separated from the ISS, and will re-enter the Earth's atmosphere in a fiery blaze over the South Pacific on September 29.
It's good fortune that observers across the U.S. will be able to watch Jules cross the sky right up to its demise. The space station is almost as bright as Jupiter and very easy to follow. The ATV should be as bright as the stars in the Big Dipper. The table below lists the times through the weekend for viewing both. As always, our unit of measurement for altitude above the horizon is your fist at the end of your outstretched arm.
The times listed are for the start of the passes, which last about two minutes for the ISS and a very brief one minute for Jules Verne, except for Monday's. Go out a little early to find your directions and get adjusted to the darkness. Good luck and let us know if you spot them.
International Space Station:
| Date | Time | Direction to look | Maximum altitude |
| Friday, Sept. 19 | starting 8:33 p.m. | south-southwest | three fists |
| Saturday, Sept. 20 | starting 8:59 p.m. | west-southwest | four fists |
| Sunday, Sept. 21 | starting 7:51 p.m. | south-soutwest | three fists |
ATV - Jules Verne:
| Friday, Sept. 19 | starting 8:59 p.m. | southwest | two fists (low) |
| Saturday, Sept. 20 | starting 9:12 p.m. | west-southwest | two fists |
| Sunday, Sept. 21 | starting 9:24 p.m. | west | two fists |
| Monday, Sept. 22 | starting 8:02 p.m. | southwest | 7 fists (3-minute pass) |
A primary and secondary rainbow formed in the drops of a sprinkler. Photo: Andrew Kirk
Andrew Kirk of California sent me an fascinating photo yesterday of two rainbows he spotted in his sprinkler. "On my morning runs I noticed that little rain-arcs formed in the water from a rotating sprinkler in the first rays of sun. So, I went back on a Saturday to take some pictures while standing in the spray. To my amazement, the pix revealed a secondary bow fragment and the brightening inside the bow," said Kirk.
I bet a few of us have noticed rainbows while sprinkling or using the hose to water our gardens, but Andrew managed to see and capture a variety of rainbow phenomena lurking there in the droplets. Nice observation Andrew and thanks for the photo!
Posted by: rking@duluthnews.com on 9/19/2008 at 9:41 AM | Comments (0) | Permalink
Noctua, voice of the night
The waning gibbous moon plays "Where's Waldo" among the limbs and leaves of a tree this morning (Sept. 18). The moon's path is now so high in the sky that it's still well up in the west during the morning hours. This photo was taken around 8 o'clock. Photo: Bob King / Duluth News Tribune
Hooo-hoo-hooo ... hoooooo hoooooo echoed through the woods last night as two great horned owls exchanged calls under the waning gibbous moon. Their voices were soft and muffled as if coming from a great distance. Few sounds fit the mood of night better than than those of owls.
It's a disappointment that an owl constellation never made it into the firmament. Most of the connect-the-dots figures we learn in the night sky were handed down from the ancient civilizations of the Middle East through the Greeks and Romans. Each has its own wonderful story to tell but sadly, the owl does not hoot among them.
Noctua the Owl made a brief appearance in Jamieson's Celestial Atlas and Elijah Burritt's popular Geography of the Heavens before disappearing from the celestial scene. Credit: Urania's Mirror published by Samuel Leigh around 1825 and based on Jamieson's atlas. Photo of great horned owl: Billy Hunt
We came close to getting an owl back in 1822, when the English amateur astronomer Alexander Jamieson changed what had been called the Rock Thrush into Noctua, the owl on his Celestial Atlas. Creating new constellations to fill in gaps between the traditional constellations had been going on since the 17th century. That was the golden age of celestial cartography, when astronomers created new star patterns from the fainter, "leftover" stars either to make a name for themselves, flatter their country's ruler (and gain favor by doing so) or celebrate a new discovery, like the invention of the electrical machine.
Fornax, the chemical furnace (left), is a faint constellation in the fall southern sky. Machina Electrica, an obsolete constellation, used to reside near Fornax. Credit: Urania's Mirror published by Samuel Leigh around 1825 based on Jamieson's altas.
Everyone was a free agent back then, and depending upon the weight of your authority, some of the newly-minted constellations were accepted, like Canes Venatici (the Hunting Dogs), created in 1687 from additional stars around the Ursa Major, and Fornax the chemical furnace from 1751. Others like Officina Typographica, created to honor Gutenberg's printing press, and Rangifer the reindeer, never cut the mustard.
After all the pushing and shoving was over, the 88 constellations that survived the melee, were officially recognized by the International Astronomical Union in 1922. Precise borders were drawn up and approved in 1930. To read more about obsolete constellations, you can click on Ian Ridpath's excellent site or visit Shane Horvatin's page.
The only constellation-inventing happening these days are what you and I create for fun. There's a big group of stars across the summer sky that I casually refer to as the spider web. Do you have any homemade constellations?
Posted by: rking@duluthnews.com on 9/18/2008 at 10:09 AM | Comments (0) | Permalink
15 minutes with the moon migration detector
This map shows the entire dome of the sky overhead flattened into a circle. The outer edge of the circle represents the horizon. Our imaginary moon migration detector is sort of like a fence the birds must cross to reach the other half of the sky. It should give us an approximate idea of how many birds pass through the entire sky during an evening of nocturnal migration. -- created with Stellarium
After reading the news about all the broadwing hawks passing over Duluth's Hawk Ridge Monday, I decided to look more closely at the moon last night through the telescope and actually count the birds I saw crossing its face (see 9/15 blog below). I observed for 15-20 minutes around 11:15 p.m. when the moon was well up in the southeastern sky. At 76x magnification, the little flapping silhouettes zipped by at the rate of one every five to 55 seconds. The average was about one bird every 15-20 seconds or three per minute. They were clearly migrating, since all the birds crossing the moon flew east to west and moved in a steady stream.
The four per minute rate, if extended later into the night, would come to about 3 x 60 minutes or 180 birds per hour. This isn't a huge number until you realize that the moon covers only a tiny portion of the sky, an amount equal to 1/2 of one degree or a half a pinky finger at arm's length. That's when I realized that to get a clearer picture of how many birds were really flying over my house, I'd have to build an imaginary moon migration detector.
The detector would consist of an arc of moons reaching across the sky from the north to the south horizons. We all know that a circle contains 360 degrees. Our arc would be a half-circle and measure 180 degrees long. Since the moon's a half a degree across, it would take 360 moons lined up side by side to stretch the distance. Still with me? Good. Now, no matter where in the east our migrating birds flew from, they'd have to pass in front of one of our imaginary moons as they winged westward.
Recall that about 180 birds per hour passed the moon last night. If we assume that same number crosses all 360 moons in our detector, the total number of birds flying through the entire sky would be something like 64,800 birds per hour. Holy heck! That's a lot of birds.
OK, ready to take one more step out on a limb? The moon was visible in a dark sky from about 7:30 p.m. last night to 5:30 a.m. this morning -- 10 hours. Just for fun now, let's say that the rate of migration didn't change at all during the night. That would mean that 64,800 x 10 hours or 648,000 birds flew over my house. Sounds crazy but who knows.
A "kettle" of hawks ride a thermal of air above Hawk Ridge in Duluth. Photo: Justin Hayworth / Duluth News Tribune
I realize these are all approximations and not solid science. I'm assuming the flight rate will be constant for the hour, and that the density of birds from horizon to overhead will average out. My estimates are also for one night only when the winds were favorable. Still it does give one an idea of how many of our feathered friends are fleeing the north for the south. It's truly exciting to think of how alive the night air above must be this month with the flutter of their wings.
Moonlight shines through a picket fence last night (Sept.16). Photo: Bob King / Duluth News Tribune
Posted by: rking@duluthnews.com on 9/17/2008 at 9:45 AM | Comments (2) | Permalink
A mystery befuddles Hubble
Looking east tonight around 9 p.m. (Sept. 16). The moon hangs two outstretched fists below the Great Square of Pegasus, the mythological flying horse. To see the Square more easily, cover the moon with one hand. Aries the Ram is the small, fingerlike constellation two fists to the left of the moon. -- created with Stellarium
These past nights of moon and clouds have been breathtaking. The way the clouds cover and then slowly reveal the moon's face, the colorful coronas and my favorite -- the sudden illumination of the landscape when the moon pops out of the clouds. I hope you're enjoying walking at night and the good smells that season the damp air.
The forecast is for clear skies tonight, and if you have the inclination, you can use the moon to help you find the Square of Pegasus and little Aries the Ram in the eastern sky from around 9 p.m. on. Moonlight will make the sky bright, but I think you'll still be able to see these constellations. I just want to get you warmed up for when the moon is out of the sky this coming weekend. We'll have places to go and things to see once darkness returns.
The mystery object photographed by the Hubble Space Telescope in 2006, before (left) and during its outburst. If you have a scientific bent, you can read the full paper by the discoverers here. Photo: K. Barbary and others, HST
You may have heard the recent news about a mystery object photographed by the Hubble Space Telescope on February 21, 2006 in the constellation of Bootes the Herdsman. The scope was focused at the time on the distant galaxy cluster CL 1432.5+3332.8, when it began to see something brighten from invisibility, shine for about 100 days and then fade back into the sky. A close study of its light with an instrument called a spectrograph rules out a galaxy, supernova or a chance alignment of stars. The mystery object doesn't seem to match anything observed in any sky survey. Whatever it is, the object brightened by a factor of 120 before disppearing - for now.
The Hubble mystery object is in the constellation of Bootes (Boh-OH-teez), well-placed in our northwestern sky just off the Handle of the Big Dipper. The map is drawn for 8:30 p.m. Arcturus is the bright, pink star in Bootes that's easily spotted even in twilight. -- created with Stellarium
Scientists love a good mystery. The first thing they're trying to pin down is its distance. That'll help establish how big a blast or burst it was. Right now estimates range from at least 130 light years to as far as 11 billion. A lot can happen within those parameters. Even if it doesn't turn out to be something exotic, our curiosity and desire to learn its origin may lead us to other unanticipated discoveries. And if our mystery does turn out to be something brand new, expect a small minority of people on Earth to devote their lives to its understanding. We are an amazing, inquisitive species.
That's why it makes sense to look up, both for professional astronomers and the rest of us. Even if you're not the first to report the next supernova in the Milky Way, letting your curiosity track among the stars will most assuredly lead to personal discoveries that deepen your appreciation of the world.
Posted by: rking@duluthnews.com on 9/16/2008 at 11:45 AM | Comments (0) | Permalink
Sol and luna face off in Two Harbors tonight
The moon, encircled by a small corona of light, shines through departing altocumulus clouds last night (Sept. 14). Photo: Bob King / Duluth News Tribune
Can't get enough of the moon? The fourth annual Harvest Moon and Sunset Watch will be tonight, Monday, September 15 along the Two Harbors breakwater near the lighthouse. 
Two Harbors is located some 20 miles north of Duluth.The event is organized by Ellen Anderson (at right), who loves watching the skies and sharing its seasonal charms. Since moonrise is around 7 o'clock, plan to arrive by 6:45 or even earlier. To get there, take a right at the third stoplight on Highway 61 through town and head toward Lake Superior. There should be signs to guide you. Aaron Bransky and Eric Norland, two amateur astronomers from the Arrowhead Astronomical Society, will be on hand with their telescopes to show the sky and answer questions.The forecast is for partly cloudy skies, which should be just fine for moon viewing.
One thing I've been up to these past few nights is bird watching. Many small birds like warblers migrate at night, which helps them avoid predators. If you point a telescope at the moon, especially around full phase, you can watch the little black silhouettes of birds flutter across the brightly-lit lunar landscape. Friday night I counted a bird or two a minute. You don't need much magnification either. I use 40x to 70x. When I drop off to bed, I think of all the birds, busy all night long, flying through that beam of moonlight to points south. Part of me wishes I could sprout wings and travel with them.
Geese head south on a fall afternoon. Photo: Bob King / Duluth News Tribune
Posted by: rking@duluthnews.com on 9/15/2008 at 9:59 AM | Comments (0) | Permalink
Feast your eyes on this harvest
During the time of Harvest Moon, the full moon rises within a half hour of sunset several nights in a row. This gave farmers the light they needed to bring in the harvest in the days before the advent of lights and heavy machinery. Illustration: Bob King
While the official date of the full moon is tomorrow, it'll actually be fuller tonight. That's because the moment of full phase is 4:13 a.m. Monday, only eight hours before the moon becomes easily visible in tonight's sky. By 8 p.m. Monday night, the moon will be 16 hours past full. Keen-eyed skywatchers might notice that by then the moon will look slightly less than round.
Either way, this is the Harvest Moon, defined as the full moon closest to the fall equinox. For Duluth and area, the moon rises this evening (Sunday) at 6:53 p.m., 28 minutes before sunset. This provides a wonderful opportunity to photograph the moon and your favorite landscape without having to use time exposures and the like.
The position of the moon is shown for the next few nights at 8 p.m. Each night the moon moves about one outstretched fist to the left (east) as it orbits the Earth. Notice that the slant of the moon's path to the horizon is very shallow. Compare with the diagram for spring below. -- created with Stellarium
The Harvest Moon is special because for several nights around Full, it rises within a 1/2 hour of sunset instead of the usual hour later each night. Monday night the moon rises only 18 minutes later than tonight. This has everything to do with the angle of the moon's path to the horizon. It's so shallow during September's full moon that the moon's daily eastward motion keeps it from plunging steeply below the horizon from night to night.
The full moon last March around 9 p.m. The angle of its path was so steep that it dropped out of the sky in a hurry instead of lingering like the Harvest Moon does. By the fourth night (23rd), it hasn't even risen yet. Compare to Wednesday in the diagram above. -- created with Stellarium
Don't believe me? Take a look at the spring path. The moon still moves a fist per night but because its angle to the horizon is pitched so high, an hour or more separates each nightly rising. The effect of the angle is especially dramatic if you compare the similar nights of March 23 and Wednesday (Sept. 17).
The moon's changing angle to the horizon finds its cause in the 23 1/2 degree tilt of Earth's axis. We orbit the sun tipped to the side as if nodding off. As we do, our axial tilt makes the sun and moon appear to move up and down in the sky during the course of a year. That changes the angle of their rising and setting paths.
With a little determination, you should be able to identify these lunar craters without any optical aid. In case you can't, don't give up. Binoculars will easily show them all.
Full Moon is also a good time to challenge yourself to find some of the moon's brightest craters. You can use this picture diagram to help you. The craters will appear as small, fuzzy bright spots in the grey lunar seas. Good luck!
Posted by: rking@duluthnews.com on 9/14/2008 at 12:28 PM | Comments (0) | Permalink
Through fog into another dimension
Fog highlights a burst of moonbeams through the leaves of a black ash tree Thursday night (Sept. 11). The moon was also surrounded by a reddish corona, caused by diffraction within the tiny water droplets that compose the fog. Details: 70mm lens at f/4, 15-second time exposure at ISO 400. Photo: Bob King /Duluth News Tribune
My older daughter and I took our dog Sammy for a walk this past Thursday night. The air was still, and light fog had begun to condense under the moonlight. My daughter's face was beautiful in the soft light. I wished she could see herself.
As we turned the corner and walked toward one of my favorite trees, we noticed a cloud of fog from a nearby field creeping across the road ahead. As it swaddled the ash tree, I glanced up and immediately stood still. Aided by the fog, moonlight shining through tiny holes and slits among the leaves burst out in a dazzling display of three-dimensional rays of light. We literally gasped.
After enjoying the sight for some minutes, I wondered if the apparition would last long enough to capture in a photo. We turned around, walked back and quickly returned with camera and tripod. Luckily, the lazy fog hung around for a good 15 minutes before slinking away. To our surprise, it also created a vivid, red-fringed corona around the moon. The best part, as any father would agree, was sharing the adventure with my daughter.
A big, bright moon simplifies the night sky. You look up and it's pretty much the moon, Jupiter and the Summer Triangle. I like that. Have you noticed how much higher the moon is getting as it approaches full phase this month? The moon is full when it's directly opposite the sun. That's why it always rises around sunset. This will happen on Monday the 15th.
In teeter-totter fashion, as the sun drops lower in the sky at the approach of autumn, the full moon moves higher. By the time of the winter solstice this December, the sun will reach its lowest point in the sky for northern hemisphere observers, while the full moon will occupy the sun's summer perch at that time. For more information on how the sun and moon chase each other around the zodiac on the celestial highway called the ecliptic, please see this past blog.
A picture from "Le Voyage dans la Lune" (A Trip to the Moon), a 1902 French silent movie considered the first science fiction film. In it, a group of astronomers travel to the moon and discover giant mushrooms and a race of insect-like creatures called Selenites. Watch the movie here -- it's a delight.
This coming full moon is the Harvest Moon, which we'll look at up close tomorrow. I also want to alert you to possible auroras over the next few nights. A stream of particles is spraying the Earth from an opening in the sun's outer atmosphere called the corona. This will probably only be visible in the far north, but just in case you're looking ...
Posted by: rking@duluthnews.com on 9/13/2008 at 10:11 AM | Comments (2) | Permalink
When you wish upon a star
Meteors streak through the atmosphere in this 19th century drawing. Most meteors are caused by pieces of rock and ice no bigger than apple seeds that plow into the atmosphere at speeds around 50,000 mph. As they vaporize overhead, they set the air aglow in a brilliant streak of light. When it comes to meteors, you get a lot bang for the buck.
It's a tradition to make a wish when we see a shooting star. I've done it and my children do too. My wish these days is for that "star" to land in my front yard as a meteorite. Most shooting stars or meteors are tiny, seed-sized bits of rock and ice shed by comets as they wend their way around the sun. The Earth sweeps through the debris and it gets cooked to white hot fury in the atmosphere. The larger pieces, which create the really brilliant fireballs, trace their origin to the asteroids, those floating mountains of rock and metal orbiting the sun in a belt between Mars and Jupiter.
Over the 4.5 billion year age of the solar system, asteroids have collided with one another and created fragments that careen in every direction imagineable. Some follow an orbit that much later takes them on a collision course with our planet. The small pieces burn up harmlessly some 70 miles overhead, but the bigger chunks can survive the fiery plunge through the air and land on the ground as meteorites.
Many meteorites still retain a black fusion crust (left) of melted rock from their hot plunge through the atmosphere. Meteorite interiors are not hot as you might imagine but retain the original chill of outer space. When cut open, stony meteorites will often reveal both metal flecking and small, spherical balls called chondrules (slice at right). Chondrules formed during tremendous heat events at the birth of the solar system, when the dust circling the sun was melted and congealed into these tiny spheres. Photos: Bob King
A fragment of the Sikhote-Alin iron meteorite that fell in Russia in 1947 (left), and a slice of the stony-iron meteorite Brahin, also from Russia. Brahin shows a beautiful mix of olivine crystals set in a matrix of iron and nickel metal. Photos: Bob King
Meteorites come in three basic varieties: stones, stony-irons and irons. Irons are what most people imagine when they think of a meteorite. They're the big, metallic masses with weird ripped and dimpled shapes. Meteor Crater near Flagstaff, Ariz. was created by the impact of an iron meteorite 25,000 years ago. Much more common however are the stone variety. They also contain minute flecks or iron and nickel but are composed mostly of minerals like olivine, a silicate of iron, magnesium and oxygen. The stony-irons are a gorgeous mix of metal and olivine crystals. Olivine, more commonly known as the semi-precious gemstone peridot, is abundant deep within Earth's crust. As we learned yesterday, there are also moon meteorites and even stones from Mars, but these are exceedingly rare compared to the other types.
Each variety represents a sample from a different depth of an asteroid. The stones or chondrites are pieces of the soil and outer crust, while the stony-irons come from the zone between the surface and core. Those hand-heavy irons are the remains of an asteroid's shattered core. Think of the battering and blasting the asteroids must have endured to get their innards to Earth. Every year, thousands of meteorites land on our planet unobserved as they plummet into glaciers, mountains and the ocean. Only a handful of falls are witnessed by us. Most meteorites rust away and decay quickly in the wet and humid conditions they meet on Earth. That's why they're terribly hard to find in places like Minnesota. The place to search is the desert, where the lack of rain low humidity can preserve them for literally thousands of years.
A new meteorite find puts a big smile on Ruben Garcia's face. Garcia, who lives in Arizona, has discovered numerous space rocks in the deserts of New Mexico and Arizona. Photo courtesy Ruben Garcia
In the last 25 years or so, amateur meteorite hunters and scientists alike have taken to the deserts to hunt for these celestial visitors. Some, like Mike Farmer (see yesterday's blog), and Ruben Garcia of Arizona, have been incredibly successful in finding these rocks from space. They're looking for dark, fusion-crusted stones that stand out from the native rock. If they find a suspect, they'll see if it attracts a magnet. That's always a good sign because many meteorites contain iron. They might grind an edge of a likely rock, and if they see tiny flecks of pure iron metal, they have cause for celebration. Almost no Earth rocks show pure iron.
An unclassified stone chondrite meteorite as found in the Dhofar desert in Oman by Eric Olson. Photo courtesy Eric Olson
Once a suspect is found, it's sent off to a university lab to be classified and given a name and specific type. So many thousands of meteorites have been discovered in the Sahara Desert in the past ten years, that many don't get classified simply because the labs are overloaded with material. While these unstudied stones are still meteorites, they're referred to as unclassified chondrites.
If you're ready to learn more about meteorite identification, don't pass up Ruben Garcia's videos on YouTube. Take a look at part 1 and part 2 of his series on meteorites that begin with an energized rock guitar intro. Dave Eicher, editor of Astronomy magazine, does a nice job explaining the basics of meteorites while showing you pieces from his personal collection on this video.
If you'd like a meteorite of your own, you don't have to spend a fortune. Ebay is a great place to purchase one for a few dollars once you know your way around. This is by no means an exhaustive list, but here are a few trustworthy meteorite dealers on eBay. Their eBay IDs are listed first: meteoritemadness (Bob Cucchiara) - specializes in inexpensive iron meteorites ; amunre (Dean Bessey) - inexpensive stone meteorites; meteorite-collector (Michael Cottingham), raremeteorites (Greg Hupe), kalani_oftheheavens, meteorite-hunter (Mike Farmer) and gipometeorites (Carsten Giessler). There are of course many more but these folks are a good place to start. If a dealer mentions he or she is a member of the IMCA (International Meteorite Collectors Association), that's another guarantee of trustworthiness. The meteorite community patrols itself closely, and is always on the lookout for fradulent claims and rocks.
There are also websites for meteorite sales. Here's just a small sampling:
And if you want to stay in touch with what's going on in the world of meteorites and meteorite hunting, there's a free online magazine called Meteorite Times, and the Meteorite Exchange, Inc. , both great resources.
There's nothing quite like holding a piece of the solar system that is not of Earth. When you realize how ancient meteorites are, and how long they've traveled among the planets to finally arrive in your hand, it'll send little chills up and down your spine. These black rocks are voices from a distant time, and hold the keys to the origin of the solar system itself. Touch one and fly away.
Posted by: rking@duluthnews.com on 9/12/2008 at 10:15 AM | Comments (2) | Permalink
Rock stars from the moon
The nearside (left) and farside of the moon. The difference in cratering is dramatic, and gives the farside the appearance of another body altogether. Photo (left) by Luc Viatour, right by the Apollo 16 astronauts and NASA
Most of the lunar seas, so-called because people thought they resembled the smooth, dark surfaces of the open sea, are concentrated on the nearside of the moon, while the farside is almost totally saturated with craters. We only see the nearside because the moon rotates on its axis at the same rate as it revolves around the Earth, always keeping one side to us. Only the Apollo astronauts have had the opportunity to see the battered farside firsthand.
Scientists still aren't certain why there are so many more maria or seas on "our" side of the moon. We do know they were created around four billion years ago by impacting asteroids and comets during the moon's formation. The seas were originally enormous craters which later filled with hot, igneous lavas that welled up through cracks in the crust. The lavas, rich with iron, were not only darker colored than the surrounding highlands (white, cratered areas) but they flowed onto the surface after much of the early bombardment of the moon had ceased. That's why they appear relatively unscared compared to the highlands. Perhaps the reason the seas are concentrated on the nearside has to do with the crust being thinner there, allowing the lavas to reach the surface more easily.
A basalt moon rock collected by the Apollo 15 astronauts. The Swiss cheese holes are called vesicles, caused by gas bubbling out of the rock as it cooled. Photo: NASA
The 12 Apollo astronauts who walked on the moon collected 2,415 moon rocks weighing 842 lbs. In addition, three Russian Luna sample-return missions netted an additional 3/4 lb. Once on Earth, the rocks were analyzed and dated using the radioactive age dating technique. They range from 3.1 billion years for the dark lavas found in the maria to 4.5 billion years for highland rocks. Ancient either way you look at it.
Professional meteorite hunter Mike Farmer of Tucson, Ariz. holds a lunar meteorite he found in 2005 in the Dhofar desert region of Oman. The talon-shaped meteorite, called Dhofar 1180, weighs 115.2g. Photo courtesy: Robert Woolard
There is one more way lunar material has been delivered to Earth -- through impacts on the moon itself. Some of the material blasted from the surface has come to our planet over time as meteorites. As of this year, independent meteorite hunters searching the deserts of the world, and scientific crews scouring Antarctica in snowmobiles, have discovered about 50 lunar meteorites with a total weight of almost 88 lbs. Scientists determine a meteorite is lunar rather than the more common variety from the asteroid belt, by studying its age, composition, mineral structure and percentage of certain isotopes (alternate forms) of elements like oxygen. Every potential lunar meteorite is sent to a lab for analysis before verified as truly originating from the moon. Rocks from the Apollo missions has helped researchers know what to look for.
Fragments of rock are welded together inside Farmer's Dhofar 1180 lunar meteorite, which originated in the heavily-cratered, lunar highlands. Scientists describe this texture as brecciated (BRECH-che-ayt-ed) or fragmented. Photo courtesy: Mike Farmer
Many lunar rocks contain countless shattered fragments of rock busted and ground up during the long period of intense asteroid bombardment in the early days of the solar system when the planets and moons were forming. Farmer's piece shows this beautifully. Lunar meteorites have greatly increased our sampling and understanding of the moon's crust and evolution. They're also a lot cheaper to obtain than launching a full-blown lunar mission. We just have to be clever and persistent enough to find them.
Another brecciated lunar meteorite called NWA (Northwest Africa) 2995. Feldspar is a common mineral in meteorites like this one from the lunar highlands. Feldspars are also found in Earth's crust. Photo: Randy Korotov
A good place to learn more about moon meteorites is Randy Korotov's excellent site at the Washington University of St. Louis. Be sure to click on this List of Lunar Meteorites link as well to see lots of photos and descriptions. To learn more about the Apollo rocks, check out this site.
The sky looks like it will clear late this evening. When it does, give our old friend the moon a fresh look. Does a moon rock lie in your future? Tomorrow we'll look at meteorites in more depth and how you might obtain one.
Posted by: rking@duluthnews.com on 9/11/2008 at 10:14 AM | Comments (0) | Permalink
Stars and pajamas
The waxing gibbous moon and Jupiter photographed shortly after sunset yesterday (Sept. 9). Details: 70mm lens, f/4.5, 1/30 second at ISO 400. Photo: Bob King / News Tribune
I'd hoped to photograph the scene depicted above more than a month ago. On my walks, I'd see the warm light of dusk reflect off the face of the building with Jupiter in the distance, but never had my camera with me. Last night I made time, and while the picture's no great shakes, it stirs something inside from long ago. Maybe it was those nights of peering through my bedroom window at Orion and the Big Dipper as a boy. I vividly remember trying to find Orion for the first time above my next door neighbor's roof when I was supposed to be sleeping. My breath bloomed on the chill glass as the Hunter's stars cleared the chimney. Not knowing any better then, I called it OR-ee-on instead of OH-RYE-en. How many of us have learned our first constellations in pajamas I wonder?
A brilliant layer of orange wreathed the western horizon after sunset last night (Sept. 9). Photo: Bob King / News Tribune
In the opposite quarter of the sky last night, twilight raged rosy and orange. I suspect we're still seeing the effects of gas and dust blasted sky high from the mid-summer volcanic eruptions in Alaska. By the time I found an open horizon, the rose-colored rays that had towered in the west had already faded. I was grateful the oranges hung in there for a few more minutes. If you go out to look at twilight colors, don't forget to watch for Venus. It's low in the west-southwest to the left of sunset and getting easier to see.
This chart shows the names of the dark patches on the moon as well as a few of the more prominent craters. Credit: Tau'olunga
When you look at the moon the next couple of nights, you can use this chart to identify the names of the dark patches called lunar seas or maria (MAH-ree-uh). People often put the patches together in a pattern that resembles a face or even an animal. The white areas are the lunar highlands, the remains of the original but heavily battered lunar crust that floated to the surface when the moon was nothing but a ball of hot magma over four billion years ago. The highlands preserve the record of ancient meteorite and asteroid bombardment. Tomorrow we'll look at what they're made of, and how enterprising meteorite hunters have found pieces of the moon right here on Earth.
Posted by: rking@duluthnews.com on 9/10/2008 at 10:46 AM | Comments (0) | Permalink
Luna and Jupiter hook up tonight / fireball update
The 8-day-old moon photographed last night (Sept. 8) during early twilight. Details: 280mm lens, f/4.5 at 1/250", ISO 400. Photo: Bob King / Duluth News Tribune
Tonight the moon guides us to the planet Jupiter in Sagittarius. Not that we really need a guide, as Jupiter is so prominent these nights in the south. The duo should grab even those who don't normally look up, because they're both so bright and close. You might want to try your hand at a landscape photo that includes the pair. Shoot shortly after sundown -- around 7:45-8 p.m. is a good time to start. You can use the information in the photo above to help you in your exposures. If you get one you like, please share your photo with us by sending it to: rking@duluthnews.com
Jupiter and the waxing gibbous moon pair up this evening (Sept. 9) in the southern sky. -- created with Stellarium
Yesterday I suggested using binoculars to look for lunar craters. Tonight is just as good as last for doing so. The best place to see them is along the terminator, the left side of the moon. At the very least, you'll be able to see a crinkly texture there made of sunlit crater rims and their shadow-filled interiors. Use the guide below to help you anticipate what to look for.
How the moon looks with the naked eye and through different instruments. The actual view in your binoculars or spotting scope will probably be even clearer than shown here. Photos by Bob King / Duluth News Tribune
After a chilly, clear night like the ones we've been having this week, you'll often awake to a dew-soaked lawn as I did this morning. As the air cools, it condenses on the tips of grass and leaves. The sparkle of sunlight among the dewdrops brings cheer to the start of the day just as the moon does to day's end.
Sunlight illuminates thousands of tiny drops of dew coating the grass this morning (Sept. 9). Photo: Bob King / News Tribune
Update for tonight (Sept. 9-10):
The SENTINEL all-sky camera recorded an outburst of bright meteors this morning, likely from the September Perseid shower. This picture is compiled from multiple video frames. Credit: NASA, Marshall Space Flight Center
NASA astronomer Bill Cooke of the Marshall Space Flight Center in Huntsville, Alabama, reported a bright outburst of a lesser known meteor shower called the September Perseids early this morning (9th) around 1:30 a.m. The Center's SENTINEL camera recorded about 25 meteors, most of which were as bright as Jupiter and Venus. Keep an eye out tonight in case the shower continues. The meteors will appear to radiate from a point in the constellation Perseus, located about one "fist" below the familiar W of Cassiopeia.
Posted by: rking@duluthnews.com on 9/9/2008 at 9:59 AM | Comments (4) | Permalink
Chuck Berry's message to ET
A horizontal world view was provided by stratocumulus clouds stacked over Lake Superior this morning, September 8. Photo: Bob King / News Tribune
We had a fine sky last night with a half-pizza moon delivered on schedule around sunset. I noticed that craters were plainly visible in my little 8x24 binoculars along the straight-edged side, called the terminator. Before full moon, the left side of the moon swells from concave to straight to convex. This is the line of advancing daylight on the moon's surface, where the sun is just rising. Low-angled sunlight brings craters and mountains into sharp relief along and near the terminator, making them an easy catch in binoculars.
It's always a wonder to me how little magnification separated the antiquated astronomical views of Aristotle from the revolution the telescope ushered in during the time of Galileo. I've never figured out what minimum magnification is needed to see lunar craters but I suspect you'd discern them even at 6x. Anyone like to try it and get back to us?
The gold-plated phonograph record (left) titled "The Sounds of Earth", and its protective cover that was attached to the Voyager planetary probes. The cover includes instructions (upper left) on how to use the stylus and cartridge to play the record as well as information on the hydrogen atom and the sun's location (bottom).Credit: NASA
On August 20 and September 5, 1977, the two Voyager spacecraft were launched on their exploratory voyages to the solar system's outer planets. Between 1979 and 1986, they sent back the most detailed views of Jupiter, Saturn, Uranus and Neptune ever taken at that time. Affixed to the outside of each craft, was a gold-plated, copper phonograph record sent as a message to possible alien civilizations who might intercept one or both ships in the distant future.
At the time, the choices for a medium were magnetic tape or phonograph record. CDs and DVDs were still in the future. Because actual physical grooves were cut into the metal, Carl Sagan, who was in charge of the project, felt a record was likely to last a long, long time without degrading. It's a typical, 12" LP but to pack more information in it, Sagan and his group decided to have the record play at 16 2/3 revolutions per minute instead of the standard 33 1/3.
One of my favorite images from the Sounds of Earth record -- the eating, drinking and licking demonstration. Let's hope the aliens have a sense of humor or they'll never come to visit. Credit: National Astronomy and Ionosphere Center
Each record contains a potpourri of sounds, pictures and music intended to give an alien a feel for the diversity of our planet. They'll find almost 90 minutes of music from a great variety of traditions and cultures, 118 photographs of our world and ourselves, natural sounds, greetings in almost 60 languages, salutations from then-president Jimmy Carter and more.
As Carl Sagan put it: "The spacecraft will be encountered and the record played only if there are advanced spacefaring civilizations in interstellar space. But the launching of this bottle into the cosmic ocean says something very hopeful about life on this planet."
31 years later, both Voyagers are at or near the edge of the solar system. In 40,000 years they'll reach the distance to Alpha Centauri, the nearest star, but they'll be cruising through interstellar space with no particular destination. It's so unlikely that anyone will ever find those records, but like Sagan, I feel hopeful just knowing they're out there.
If you'd like to learn more about the record as well as sample the sound recordings and images, click here and then explore the links in the top left of the page. You'll find a list of the musical selections but sadly, no sound links. Since my favorite part of the record is the music, I've provided links below to a few of the selections. These are not necessarily the original tunes included on the spacecraft but they are versions of the same.
* Chuck Berry's "Johnny B. Goode" (great early video!)
* El Cascabel (My Rattlesnake Rattle) from Mexico (These dudes can play.)
* Queen of the Night aria from Mozart's opera The Magic Flute
* Panpipe music from the Solomon Islands (good panpiping starts about 4 1/2 minutes in)
* First movement from Beethoven's 5th Symphony
Posted by: rking@duluthnews.com on 9/8/2008 at 10:04 AM | Comments (0) | Permalink
A 550-ton weight over my head
A mountain-like cumulus congestus cloud rises up into the blue sky yesterday afternoon (Sept. 6). Clouds like these tower to 15,000 feet or more and can measure many miles across at the base. Photo: Bob King / News Tribune
There was serenity in the air yesterday despite enormous cumulus clouds that moved through our region. Some of these grew dark and let loose brief showers. A particularly fine line of cumulus congestus clouds bubbled up north of Duluth in the early afternoon. It was fun to watch their multiple turrets expand like marshmallows over a campfire. This was best visible in a pair of 8x24 binoculars I keep handy. Through them, the expanding clouds were magnified into ever-changing shapes and movement. This was particularly evident along the clouds' edges, where small protuberances morphed nonstop or dissolved into nothing in real time.
You have to concentrate a little but once you get the feel for the pace of cloud changes, it's like seeing an explosion in slow motion. Watching a cloud evolve requires patience which is why binoculars are useful. They help by magnifying these movements. The same could be said of watching a star move in the sky at night. With a power pole in front of you to artificially eclipse the star, you'd be surprised how long it takes to re-emerge on the other side. Stars are carried through the sky by Earth's rotation at a rate of one outstretched pinky finger every four minutes. Try it sometime.
Typical cumulus clouds like these each contain about 137,500 gallons of water. Credit: Photos.com
Cumulus clouds are born from moist, warm air rising from the Earth's surface. As the air rises, it cools, reaches the dewpoint, and condenses into cloud. Strong air currents fed yesterday's cumulus to towering heights. Ever wonder what clouds weigh? I did some checking and was surprised to learn that a common, fair weather cumulus cloud contains some 550 tons or 137,500 gallons of water, all in the form of buoyant vapor, according to Peggy LeMone, senior scientist at the National Center for Atmospheric Research in Boulder, Col. The cumulus congestus cloud in the top photograph tips the scales at 5,500 tons or 275 million gallons.
We've talked here before about clouds on Mars and other planets but I recently came across a short video (right) of water ice clouds moving through the thin Martian atmosphere taken by NASA's Phoenix lander. They resemble our familiar cirrus clouds, also composed of ice crystals. The camera took these 10 frames over a 10-minute period during the afternoon of August 29. Water vapor for the clouds' creation comes from Mars' northern polar cap during the peak of the Martian summer. The vapor forms clouds, fog and frost.
Current temperatures in early September at the Phoenix landing site in the Martian arctic range from highs around 17 below zero during the day to a low of 117 below at night. Yeah, that's cold enough for frost!
A light frost coats the Martian soil and rocks next to the Phoenix lander in this image taken last month just before 6 a.m. local time. The frost vaporized shortly after the sun rose over the lander site. Photo: NASA/JPL-Caltech/University of Arizona/Texas A&M University
We'll soon be seeing frost here but hopefully not before we get our gardens in. Gardening for future Mars inhabitants will likely consist of the artful tending of fine gravels and sculpted rocks much like the folks in southern Arizona do now. I'd miss my beans.
Posted by: rking@duluthnews.com on 9/7/2008 at 9:53 AM | Comments (0) | Permalink
A dead rock comes to life
This map shows the sky tonight (September 6) around 8:30 p.m. looking south-southwest. The red star Antares, which marks the heart of the scorpion, will make a pretty duo with the moon all evening. -- created with Stellarium
I'm getting partly cloudy skies from the Clear Sky Chart forecast for tonight. That should at least give us a shot at seeing the first quarter moon pair up closely with the bright star Antares in the constellation Scorpius. Scorpius gradually becomes harder to see this month as Earth's orbital motion around the sun causes the constellation to sink into the western sky. The moon moves eastward from Scorpius to the Sagittarius Teapot over the coming nights. Watch for it to snuggle up to Jupiter next Tuesday the 9th.
A sequence of images of the asteroid Steins taken last night (Sept. 5) by the Rosetta wide-angle camera during its brief flyby. Like so many moons and planets, Steins is peppered with craters from meteorite bombardment during the formation of our solar system. Credit: ESA
The European Space Agency (ESA) had great success last night when its Rosetta spacecraft made a 30,000 mph flyby of the asteroid 2867 Steins en route to a comet rendevous in 2014. The event took place 225 million miles away in the asteroid belt between Mars and Jupiter. Everything worked smoothly except for the closeup camera which unexpectedly stopped running.
The craft flew only 500 miles away from the 3-mile-diameter, diamond-shaped rock. Despite its small size, check out that huge crater on top, more than a mile across. Scientists are trying to figure out why the asteroid wasn't completely blown apart by the impact. There's some tough rocks out there in space.
An artist view of the Rosetta spacecraft above Comet Churyumov-Gerasimenko with the lander in the foreground. The craft will arrive at the comet in 2014. Credit: ESA
Rosetta, which is named after the famous Rosetta stone that helped us understand Egyptian hieroglyphics, will visit another asteroid in July 2010 as it plys its way to its ultimate aim, Comet Churyumov-Gerasimenko (C-G). When it arrives in 2014, it will deploy a craft to orbit the comet's core, called the nucleus, and a lander to study the comet's surface. To learn more about the mission and view a wonderful video and more photos of the flyby, you can visit this website.
I hope I'm around when it all happens. In the early 1980s, Comet C-G was one of the first to really fire my interest in these tailed wonders made of ice, dust and rock. Through my telescope, I watched the comet creep across the starfield night after night, develop a short tail and finally fade from view. Landing on a comet sounds positively Jules Vernesian. That's why science is so much fun -- our most wide-ranging dreams become realities through curiosity, experimentation and hard work. I always feel grateful to the people behind these space missions. Their drive and labors produce results that excite the imagination and expand our world view.
Posted by: rking@duluthnews.com on 9/6/2008 at 9:36 AM | Comments (0) | Permalink
Wiggle, jiggle and jive
We've all heard the song Twinkle, Twinkle Little Star, an English nursery rhyme that shares its melody with several others, including the Alphabet Song. Astronomers enjoy nursery rhymes like anyone else but they bristle when the subject turns to twinkling stars.
Go out just about any clear night, look up and you'll see the stars a-flutter. Twinkling is caused by pockets of warm and cold air mixing and moving in our usually turbulent atmosphere. 
Starlight streams blissfully through space until it strikes the airy envelope above us. There it gets tossed around like a hot potato by air cells of different temperatures and densities on its way to our eyes. The cells act like lenses, and refract or bend a star's light momentarily this way and that, causing the star to temporarily brighten and fade. Stars can even flash different colors. Each color of a star's light is refracted to a different degree, causing the dominant color to vary moment to moment. (Illustration courtesy The WEATHER DOCTOR, www.islandnet.com/~see/weather/doctor.htm)
Ever look at a bright star near the horizon? The best is the brilliant, white star Sirius of the winter sky. You'll be treated to a frenetic display of green, red and blue flashes if the air is especially turbulent. Binoculars make the colors stand out even better.
Stars that are high up in the sky twinkle the least, while stars low to the horizon twinkle the most because they have to pass through a much greater thickness of atmosphere. Illustration: Bob King / News Tribune
All stars twinkle, but since most are relatively dim, only the brightest ones show it plainly. On late summer nights, look in the western sky for pink Arcturus. It's a good flasher, as are the stars of the Big Dipper in the northwest. Stars that are high in the sky twinkle less because they have less atmosphere to penetrate. Stars closer to the horizon are the best twinklers because their light gets jived around by literally hundreds of miles of dense air, winds and shifting cells before it reaches our eyes.
Planets twinkle the least because they have disks big enough to thwart the moving air cells and not get pushed around. Stars are mere points even in the largest telescopes, and much more susceptible to refraction.
Not only do stars get "moved around" by the air but it also blurs them. Astronomers taking pictures of stars and galaxies had to deal with soft images for over a hundred years until telescopes like the Hubble were developed that could observe above the atmosphere. With no air in the way and its optics corrected, Hubble takes the sharpest images ever.
A star in the Hubble scope (left). The same star in a typical Earthbound scope (right).
A photograph of the core of the globular cluster M13 in Hercules taken with the Canada-France-Hawaii telescope with (top) and without adaptive optics technology. Photo courtesy of Gemini Observatory and Canada-France-Hawaii Telescope/Coelum/Jean-Charles
Let's not stop there. Astronomers have devised what are called adaptive optics (AO) on most of the newer telescopes. A special sensor detects the tiny wiggles in starlight at a rate of almost a 1000 times a second. This information is sent to a computer which commands a flexible mirror to change its shape just that quickly to compensate for atmospheric distortions. The cleaned-up starlight is beamed to the main mirror and into the CCD camera for recording. Slick indeed.
Amateur astronomers still have to contend with blurry stars on many nights since there's no affordable AO just yet. That's why we jump up and down when the atmosphere is less turbulent than normal, and stay at the telescope's side until dawn if we can. On those nights, the stars are crisp and steady, and the planets seem so close you almost feel like you're there.
Wishing you steady skies!
Posted by: rking@duluthnews.com on 9/5/2008 at 11:01 AM | Comments (2) | Permalink
The truth about astronomy
The sky was mostly cloudy last night despite the optimistic forecast. Keep in mind that Neptune and the Andromeda galaxy will be visible throughout the fall. By the beginning of next week, the moon will make viewing Neptune difficult for a time. I'll make another map for finding the planet when the sky is moonless again later this month.
Tomatoes hang on a few more days in the garden before they're devoured. Photo by Bob King
Summer's been good to my garden. Just look at that bunch of tomatoes. Their color bursts as brightly as their taste soon will. We delight not only in fresh vegetables but also in the incredible variety of colors that surround us. Emerald green spring leaves, vibrant yellow-orange goldenrods, blue eyes and fall leaves.
Hubble Space Telescope photo of the Orion Nebula (left). Stars within the nebula cause the gases to fluoresce pink and green. The re-worked picture (right) shows the subtlety of the color as seen in a large amateur scope. This is what you really see. Photo: HST
This same vivid color scenes play out in many astrophotographs, particularly those taken with the Hubble Space Telescope. These pictures are lengthly time exposures made on sensitive CCD arrays that record the subtle colors in galaxies, nebulas and planets in spectacular fashion. Unfortunately these images often set up high expections when a new observer looks through a telescope for the first time. Except for the moon and several of the planets, most objects in even large amateur telescopes are virtually colorless.
The Ring Nebula in Lyra the Harp. Hubble shows a rainbow of colors. Through an amateur's telescope, the Ring is still very beautiful but pale grey. Photo: HST
The brightest part of the Orion Nebula, one of the brightest gas clouds out there, is pale green with a hint of pink in large telescopes. Our eyes see things in real time, while a photograph accumulates light. Astronomical objects are generally faint so the colors, though present, don't register in our eyes. A camera is an eye that can stay open all night, piling up photon after photon to create a well-exposed, colorful image.
Jupiter through the Hubble scope (left) and how it appears in real time to the eye (right). Photo: HST
Things are different with the moon and planets. They're bright enough to show their true colors, so to speak. The moon reveals pale and deep greys, yellows and even a bit of green (cheese maybe?) Jupiter looks yellow, and its bigger cloud belts are a rich reddish-brown. And Mars, while not red, as seen in many photos, is certainly orange.
Should we be disappointed that the astronomical world looks so grey? Absolutely not! I love photos of all the critters of the universe. They inspire. But to see for oneself the delicate appearance of a galaxy, its core a tiny light of compressed starlight, is to experience the REAL thing, better than a photograph by far. Colorful or not, the soft tendrils of the Orion Nebula are a spectacular aspect of nature that literally touches our eyes as we gaze through the telescope. The world as it is is just fine by me.
Posted by: rking@duluthnews.com on 9/4/2008 at 10:57 AM | Comments (0) | Permalink
Neptune in binoculars? No way!
So the sky did crack open a few times last night between waves of fast-moving clouds. The stars were very bright in the hazeless air. Finding things in the sky mostly depends on good maps and a little persistence. Everything's complicated by the spinning of the Earth, which like the classic mother-in-law stereotype, keeps moving the silverware. 
Over the coming week before the moon fattens up, we have a ideal opportunity to find planet number eight in a pair of binoculars.
Neptune (at right) was discovered on September 23, 1846 by Johann Galle at the Berlin Observatory based on a mathematical prediction by French mathematician Urbain LeVerrier. Astronomers had observed irregularities in Uranus' orbit and based upon those, predicted the existence of an outer planet. Amazingly, Galle found the planet within one degree of the prediction. British mathematician John Adams independently came up with a similar solution, so the the discovery is shared jointly by the two men.
Looking south around 10-11 p.m. in early September. Step one in your quest to find Neptune is to use brillliant Jupiter and the star Altair, located at the bottom of the Summer Triangle, to form a triangle with the stars Alpha and Beta in Capricornus. Two fists to the left or east of Alpha-Beta, you'll find Delta. If you get this far, use the detailed map below to zero in on Neptune. -- created with Stellarium
At 2.7 billion miles from Earth and about four times our size, Neptune is a mid-sized planet like Uranus. Beneath its hydrogen, helium and methane atmosphere, it's composed of a mix of ices and rocks. For more on Neptune you can re-visit this blog.
Finding Neptune requires at least moderately dark skies and a pair of 7x50 or 10x50 binoculars. The key is the aperture or size of the lenses of your binoculars. The number '50' in 10x50 stands for the lens size in millimeters. 50 millimeters equals about two inches. You're going to need that size lens or larger to spot the planet. The '10' in 10x50 is the magnification. Anywhere from seven on up is good. 10 power is ideal.
A binocular view of the sky near Delta. Point your binoculars at Delta and move them upward just a bit to find what I call the "index finger". To the right of the finger, you'll find a triangle of dim stars. Look for three stars in a row there. Neptune is the "star" in the middle of the row. -- created with Chris Marriott's SkyMap Pro at www.skymap.com
OK, let's give it a try. We always start with the brightest thing you can see. That's Jupiter and it's blazing in the south. Use the first chart to get you to Delta in Capricornus. The second, closeup chart (above) will point you to Neptune. Remember to allow your eyes time to get used to the dark before you attempt this challenge. 10-15 minutes is good. It's also important to focus sharply on the stars and brace the binoculars against a wall or car to keep them steady.
Over the next few nights, Nepture will move ever so slowly westward (to the right), breaking the neat line it makes tonight. It'll stay in the neighborhood for some time however since the planet takes 165 years to go just once around the sun.
If you have success, I congratulate you! What the heck, you deserve a pat on the back just for trying. And of course we'd love to hear of your experience whether you found the planet or not. Just add your comment by clicking on the link below.
Posted by: rking@duluthnews.com on 9/3/2008 at 9:30 AM | Comments (0) | Permalink
Stridulations in C major
I know nothing about composing music but given a second life, I'd learn how to do it. Modern classical is my favorite, and I marvel at how composers wring such amazing color and vitality from musical instruments. Music buzzed the air last night, but instead of clarinets and timpani, it was legs, wings and bodies of the night insects. The combination of heat and high humidity brought their ardor to a crescendo that lasted the entire night.
The word stridulation instantly came to mind. Stridulation sounds like what it means -- the rubbing together of body parts to produce sound. Katydids and crickets are superb stridulators, and if you live near an open field or can get to one, the zip-zips, tch-tchs, chirps, buzzes and raspings are positively symphonic. I stood still, closed my eyes and tried to hear each instrument of the orchestra but the multiple layers of sound were almost too dense to decipher. Only by walking over to a less crowded stage, could I discern the individual voices of the performers.
To find the Andromeda galaxy, face east around 9:30-10:30 p.m. and locate either the W-shaped constellation of Cassiopeia or the Great Square of Pegasus. The right half of the W points like an arrow to the galaxy, which is located two outstretched fists away. Andromeda will be visible the remainder of the summer and fall. -- created with Stellarium
The insects will perform again tonight but without the accompanyment of a clear sky. Tomorrow's forecast looks much better. That's good because I hope you'll take the next opportunity to spy the Andromeda galaxy, one of late summer sky's finest deep sky objects. We talked yesterday about Edwin Hubble's discovery of the galaxy's true distance. At 2.5 million light years, Andromeda is the most remote object most of us will ever see with the naked eye.
This photograph shows the W of Cassiopeia and its relation to the Andromeda galaxy. The galaxy is a flattened disk just like the Milky Way. The bright center, called the nucleus or central bulge, is packed with even more stars than the disk and glows brightly. Below the left half of Cassiopeia, you can find the Double Cluster of Perseus. Details: 35mm lens, 30-second time exposure at f/2.8, ISO 800. Photo: Bob King / News Tribune
The galaxy is also known as M31, the 31st entry in Charles Messier's catalog. You'll often see it referred to by that number in astronomy texts or deep sky catalogs. Andromeda is a spiral galaxy and home to many billions of stars, star clusters, gas clouds and undoubtedly solar systems just like our own galaxy, the Milky Way.
You'll need to get away from downtown lights to find Andromeda. Neighborhoods like Morgan Park, Park Point and Lakeside are good places. A short drive to a dark, country sky is even better. If you can see the Milky Way, you'll find Andromeda. It's not hard.
Go out about 9:30 or later, face east and use the map and photo above to get you there. You'll be looking for a fuzzy glow about a finger width across that looks like a chunk of the Milky Way set adrift. Once you find the galaxy, see if you can make out its brighter center by looking around it rather than directly at it. As you gaze at Andromeda, consider that the light touching your retina left the galaxy over two million years ago, when early humans were hewing stone to make the first hand axes.
The Andromeda galaxy and its two companion galaxies. Andromeda and the Milky Way galaxy are hurtling toward one another at 310,000 miles per hour and will collide in about three billion years. Don't worry too much about it. Stars won't hit stars. Instead, giant gas clouds in both galaxies will compress into a whole new generation of stars. Photo: John Lanoue
Seeing into deep space is like stepping into a time machine. It allows us to experience the past through our sense of sight. You'll also notice that Cassiopeia leads you to another fuzzy glow called the Double Cluster, a pair of two star clusters in Perseus. We'll take a closer look at it in a future blog.
Finally, I'd like to share a photo taken by Lyle Anderson here in Duluth with his first digital camera. Thanks Lyle for sending your picture!
Orion's Belt peeks above a neighbor's house in this photo taken during the early morning hours last week with a Canon EOS Rebel XT, 18mm lens and 20-second time exposure. Photo: Lyle Anderson
Posted by: rking@duluthnews.com on 9/2/2008 at 9:50 AM | Comments (0) | Permalink
Beacons to light the way into deep space
Venus, Mercury and the crescent moon scrape the western horizon tonight (Sept. 1) at 8 p.m., 15 minutes after sunset. Venus lies three fingers, held out in front of you, above the horizon. The sky will be bright at this time, making the moon and Mercury very difficult to spot. If you don't find them, you can at least see Venus, especially toward 8:15-30 p.m. -- created with Stellarium
If you can find an open western horizon tonight, you might be able to see the conjunction of the thin crescent moon, Venus and Mercury. The only one you might call easy is Venus. Mercury will require binoculars and the moon is lower yet, and may not even be visible from our region. You like a challenge, right? Those who might be reading this in the southern U.S., where the moon makes a sharper angle to the horizon, will find the conjunction much easier to observe.
Once upon a time, the universe was a cozy place with Earth at its center. Then around 1543, Copernicus put the sun there and the Earth in orbit around it. Later we came to understand that the sun was just one of many billions of stars in a gigantic, flattened disk called the Milky Way galaxy. With the invention of the telescope, astronomers began finding fuzzy, spiral-shaped objects through their telescopes whose nature puzzled them. Some thought they were galaxies like our own but very remote, while others considered them nearby gas clouds in the Milky Way itself. No one could determine the distance to any of the fuzzies to answer the question. Triangulation methods didn't work.
And that is where things stood 100 years ago. Then 
in 1908, Henrietta Swan Leavitt (left), working at Harvard College Observatory, discovered the first Cepheid variables in two satellite galaxies of the Milky Way. You'll recall from Friday's blog that Cepheids are giant, pulsating stars whose brightness varies over a steady and regular period. Our featured star, Eta Aquilae, goes from bright to faint to bright again in 7.2 days. Henrietta discovered that the brighter the Cepheid, the longer the period. Short periods meant dim Cepheids, long periods, bright Cepheids.
A year later, astronomers determined the distances to several nearby Cepheids through other methods. With this information in hand, they could now find the distances to Cepheids much further away. It works like this. If you know how bright something really is and how bright it appears, you can find how far away it is. Say Cepheid A with a period of five days and a brightness of 10 is 300 light years away. Cepheid B with the same period but 100 times fainter would be 10 x 300 light years or 3000 light years from us. The reason why you multiply by 10 instead of 100 is that light drops off with the square of the distance. Details, details.
Astronomer Edwin Hubble with a photograph of the Andromeda Galaxy. AP Archive
Cepheids are brilliant stars that shine across vast distances, making them a very useful cosmic yardstick. That's where American astronomer Edwin Hubble comes into the picture. He was convinced that the little fuzzies astronomers saw were far-away galaxies. 
The way he proved it was by taking long time-exposure photographs of the biggest fuzzy of them all, the Andromeda Galaxy, back then called the Andromeda Nebula. On October 5, 1923, Hubble photographed his first Cepheid (marked VAR with an exclamation point on the photo at right) using the 100-inch Mt. Wilson telescope, the largest in the world at the time. When he calculated its distance based on period and brightness, he discovered that Andromeda was over a million light years away, far too distant to be part of the Milky Way.
In one great leap, Hubble's and Leavitt's discoveries forever enlarged our universe beyond anything anyone had imagined. And what about those other fuzzies? They're even further -- millions to billions of light years distant.
The Andromeda Galaxy and its two companion galaxies, M32 (upper left) and NGC 205. Andromeda is a spiral galaxy similar to but larger than the Milky Way. Photo credit: Frank Barrett
These days the distance to the Andromeda Galaxy has been refined to 2.5 million light years. Incredibly, you can actually see it with your naked eye. Stop by here tomorrow for a helpful map and guide on how to get there. Good luck on tonight's planets!
(Henrietta Leavitt photo from American Institute of Physics, Emilio Segre Visual Archives. Andromeda photograph from Mt. Wilson Observatory historical archive)
Posted by: rking@duluthnews.com on 9/1/2008 at 9:42 AM | Comments (0) | Permalink
