Monthly Archives: February 2011

How to shoot your own space station photos

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This photo shows yours truly at the telescope during a space station twilight pass. The exposure time was 30 seconds, the longest available in manual mode on my camera. Photo: Bob King

The space station photos we featured yesterday inspired me today to write a little guide on how just about anyone can take a picture of the orbiting ship.

With a little luck in the weather department and a bit of advance planning, you might surprise yourself at how easy it can be. The station is bright and will show up even during relatively short exposures.

Here’s what you’ll need to photograph it:

  • A camera that you can set to manual mode to do a time exposure. Many point-and-shoot digital cameras allow time exposures up to 15 seconds.
  • A tripod to mount the camera on so it’s rock-steady when you take the photo.

A typical point-and-shoot style camera set up on a basic tripod. Photo: Bob King

First, make sure your camera is in the default wide-angle view setting, so you can capture as much of the station’s path across the sky as possible. No zooming is needed. Most cameras automatically go to wide view as soon as they’re turned on. Then, with the camera in manual mode, set the shutter speed time to 15 seconds or higher.

Next, set your lens to “wide open” to allow the maximum amount of light through. Depending on your camera, that setting might be f/2.8, f/3.5 or f/4. The lower the number, the faster your sensor records light. Almost all modern digital cameras allow you to manually set the lens opening and shutter speed.

Finally, change your ISO, a number describing the sensitivity of your image sensor, to 400 or 800. If you go higher, the image will look grainy; lower and you might not record your target.

For information on how to change these settings, consult your camera manual. You still have that, right?

This week the ISS will be crossing the northern sky moving from west to east. Go out about 10 minutes before the pass begins and compose your photo with some trees, your home – anything interesting in the foreground that also includes a swath of the north-northwestern sky.

When you see the station coming into view in your camera frame, carefully press down the shutter button to take the picture. Since a pass typically lasts several minutes, you might find you have time to make several exposures.

This picture of the ISS crossing the northern sky was taken on the "bulb" setting and exposed for about two minutes. Photo: Bob King

If the sky is dark at the time, you should easily capture a section of the space station’s path. It will appear as a short streak of light during a 15 or 30-second exposure. Higher-end cameras have what’s called a “bulb” setting, where you can leave the shutter open as long as you like and record a pass from one end of the camera view to the other.

Things get trickier in bright twilight. That’s when you have to be careful not to overexpose and wash out your image. Trial and error will tell, but dialing your ISO down to 200, setting your f-number to 4 or 4.5 and shortening your exposures will still give you a usable picture.

The space station will appear in the northwestern sky over the Duluth region tonight starting at 7:35 p.m. Why not bring your camera along for the ride?

Venus-moon spectacle and amazing shuttle rendezvous photos

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The moon passes Venus the next two mornings in the bright dawn sky. Created with Stellarium

If you’re out at dawn the next two mornings you’ll see a lovely sight in the southeastern sky as the crescent moon passes near the planet Venus. Tomorrow it will lie some six degrees to the right of the planet, while on Tuesday the crescent will be four degrees to the left.

Venus looks like a smooth, white gibbous moon in a small telescope. Credit: Chris Marriott's SkyMap

Venus, while still brilliant, has been steadily drawing closer to the sun over the past month as its distance from Earth increases and the angle it makes between us and the sun diminishes. At the same time, the planet’s phase waxes from ‘half moon’ to gibbous. A small telescope will easily show its egg-like outline.

Because Venus is perpetually shrouded in highly reflective clouds, we never see its surface. Amateur astronomers using special ultraviolet filters can photograph textures in the clouds, but they’re rarely seen visually. Overcast skies combined with Venus’ relative closeness to Earth are the reasons it’s the brightest planet.

Coal has an albedo of 10% making it nearly as dark as the moon.

Astronomers rank how reflective an object is by its albedo (al-BEE-do). A body that reflects 100% of the light it receives has an albedo of 1. Venus’ albedo is .75 so it reflects 75% of the light it receives from the sun. In contrast, the coal-dark moon reflects only 12% of the sunlight falling on it. The brightest object in the solar system is Saturn’s icy moon Enceladus with an albedo of .99.

Curious about Earth? Dark soil reflects about 5% of sunlight and virgin snow 95%. Averaged out, our planet’s albedo is .37  – a dim world compared to Venus.

I’m very happy to share this spectacular photo taken by Mónika Landy-Gyebnár
of Veszprem, Hungary yesterday evening. Unlike U.S. observers, Monika got to see the space station and Discovery shuttle in the evening sky shortly before they docked.

This sequence of pictures show the Discovery shuttle and space station 'neck in neck' shortly before the shuttle docked. Details: 20mm lens at f/2.8, 1.3 second exposures at ISO 200. Credit: Mónika Landy-Gyebnár

She describes the scene: “The spacecraft were at about 1/4 degree separation, so really close! I’m unable to describe how beautiful they were! It was the greatest experience I had since the total solar eclipse of 1999.”

The trails of the spacecraft are broken into segments, because Mónika shot multiple exposures, each 1.3 seconds long, which she later combined into a complete trail. One-quarter of a degree is just half the width of the full moon, so that’s amazingly close. I can only imagine the sight! If you didn’t or couldn’t see it, don’t fret. We’ll have another opportunity when the two craft part before the shuttle returns next Sunday.

What an image! Rob Bullen of Gloucestershire, England photographed Discovery (left) and the ISS through his 8-inch telescope shortly before the docking. More info below. Credit: Ron Bullen

“It’s taken many years and many hundreds of frames to get an image of the shuttle like this,” said Bullen in an e-mail this afternoon.  “I regularly image the station but have never been able to get as clear an image of the shuttle as I did last night (it usually just looks like a bright shapeless blob attached to the station).”

Rob and Mónika, we appreciate your efforts and thank you for sharing the results with our readers.

As long as we’re on the topic, I hope you got to see the bright pass of ISS-Discovery Saturday night. More information on upcoming passes can be found in yesterday’s blog.

I finally caught the solar sail NanoSail-D last night. Hah! Just barely. My vigil for this hard-to-catch satellite took place in the frozen wastes north of Duluth where the sky was very dark. I watched for anything along its path from Andromeda through Aries and into Cetus and caught one brief, bright, 1st magnitude flash to the west of Aries. That was it! Our next chance to see it will be Monday. I’ll post a finder map tomorrow.

Sweet sounds of flute 217 miles overhead

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Watch a 3-minute interview with astronaut Cady Coleman and listen to her play the flute in orbit.

We nailed it. Clear skies in the nick of time made it possible for me and my work colleagues to spot both the International Space Station (ISS) and Discovery shuttle from downtown Duluth yesterday evening.

Tonight the two ships will appear as single moving light after they dock this afternoon at 1:16 p.m. CST. If you happen to have a flyby for your location shortly before that time, you’ll see them neck in neck as they arc across the sky.

With a cloudy Earth as backdrop, Discovery makes its final rendezvous with the ISS this afternoon. Credit: NASA

As you follow the space station in the evenings ahead, picture a combined crew of 12 astronauts living and working there for the next 10 days. When astronaut Jeff Williams spoke in Duluth several weeks back, he described the arrival of a new crew like a visit from your family – you’re thrilled to see them again but happy when they finally leave for home.

Flight engineer Cady Coleman, who was born in Charleston, South Carolina and is currently aboard the ISS, likes to bring her flute along when she space travels. She owns several, including one played by Ian Anderson of the band Jethro Tull.

“It is really different to play up here,” Coleman said. “I’ve been having the nicest time up in our Cupola. I float around in there. A lot of the times I play with my eyes closed.”

Astronauts have plenty of free time when they’re on the ISS for months at a time. Playing a musical instrument makes the place feel a lot more like home.

Here are Central times for viewing ISS-Discovery from the Duluth area. For times for your town, click HERE and key in your zip code. The pair will travel from west to east across the northern sky.

* Tonight starting at 6:42 p.m. A bright pass!
* Sunday Feb. 27 at 7:08 p.m. The station will fade as it enters Earth’s shadow near the middle star in the Big Dipper’s handle.
* Monday Feb.28 at 7:35 p.m. Station fades and disappears about one outstretched fist below the North Star.
* Tuesday March 1 at 6:26 p.m. A second brief pass in the northwestern sky only begins at 8:01 p.m.
* Wednesday March 2 at 6:52 p.m.
* Thursday March 3 at 7:19 p.m.
* Friday March 4 at 6:09 p.m. at sunset. Bright pass but the sky may be too light to see. Second shorter pass in the northwest at 7:45 p.m.

As far as NanoSail-D I had no luck. Conditions were ideal, but nothing was visible, even in binoculars. Perhaps the sail passed over with its edge facing us making it too faint to see. Another observer wrote from Ohio that she was able to see it near Betelgeuse in Orion.

The Whirlpool Galaxy, located near the end of the Big Dipper's handle, is aptly named. One of its spiral arms extends in front of the companion galaxy NGC 5195. The Whirlpool is some 60,000 light years across or about 60% as big as the Milky Way and 23 million light years from Earth. Credit: NASA

My teeth were chattering last night after an hour and a half in 10 below temperatures observing Saturn, the Whirlpool Galaxy, and a new supernova in a distant galaxy in the constellation Crater the Cup. After packing the scope away, I stood outside a few more minutes and let myself feel winter’s knife-edge. Nature can really get intense, but that’s OK. There’s satisfaction in survival.

Shiny birds skim the sky tonight

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NanoSail-D is the streak slicing across middle of this time exposure photo taken on February 19 by Vesa Vauhkonen, who lives in Rautalampi, Finland. The Pleiades star cluster is at upper left.

Will it be clear or won’t it? Always the question in the astronomer’s life. Last night I had hoped to get home early enough from work to see NanoSail-D, a 100-square-foot polymer solar sail in orbit around the Earth. I missed it by five minutes.

The 100 square foot NanoSail-D is shown in orbit around the Earth in this photo illustration. Credit: NASA

NanoSail-D was deployed by NASA earlier this year and has been making passes across the sky just like the space station and shuttle. Unlike them, its brightness is unpredictable. Sometimes you need binoculars to see it, other times it catches the sun’s rays just right and flares nearly as bright as Sirius, the brightest star. Observers report that it constantly changes brightness – flickering almost – as its orientation in relation to the observer and sun changes.

“The great variation in brightness is due to its shape; it is a large, thin sheet of highly reflective material. Seen edge-on, it is faint, but seen face-on at a favorable sun-angle, it may rival the brightest stars,” says Dean Alhorn of the Marshall Space Flight Center in Huntsville, Alabama.

The sail skims the rarefied top of the atmosphere and will eventually burn up like a meteor in April or May through friction with the air. NASA is testing NanoSail-D as a prototype “drag sail” that could be packaged with orbiting satellites to help them safely “de-orbit” when they’ve outlived their usefulness. Consider the technology a controlled way to get rid of space junk.

Tonight the solar sail passes from Perseus (top) through Taurus the Bull, right next to bright Betelgeuse in Orion and then to the right of Sirius. Some of the times shown are expanded to include seconds. The sail will look like a moving star that fades and brightens. Charts created with Stellarium

Lately, NanoSail-D has been making convenient passes over the region during evening hours. I’ve created two sky charts to help you find it tonight and tomorrow night. The forecast is scaring me, but amateur astronomy is all about preparation in case the weather cooperates.

On Saturday evening the 26th, the sail will track lower across the western sky, cutting straight through the little constellation of Aries the Ram.

To prepare for the passes, grab your binoculars and go out at least five minutes in advance to allow time for your eyes to adjust to the darkness. If you’re uncertain exactly where to look, center your binoculars on a star or patch of sky you’re familiar with and just wait for the sail to come by. Betelgeuse in Orion will serve nicely tonight.

The sooner you find the sail, the better chance you have of catching a flare and watching its funky brightness variations.

Just a reminder. The International Space Station will make a brilliant twilight pass over the Duluth region this evening (Friday) starting at 6:15 p.m. Watch for it to rise in the northwest, pass overhead at 6:18 and then drop away in the southeastern sky. 18 minutes later at 6:33, the space shuttle Discovery will cruise fairly high across the northern sky.

If you don’t see the shuttle at that time, wait 10 minutes. Two different websites’ prediction times for Discovery are 10 minutes apart for some reason.

To find out when our three featured ‘birds’ fly over your town, please go the Heavens Above website, log-in, select your city and then click on the ISS, STS-133 (Discovery) and NanoSail-D links.

Now, will the weather be clear?

Discovery carries first non-human passenger into space

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Discovery heads to orbit after takeoff as seen from Smyrna Beach 40 miles north of the launch site. Credit: JeRay Johnson

Everything went A-OK during Thursday afternoon’s launch of the space shuttle Discovery from the Kennedy Space Center in Florida. Even 40 miles away, the shuttle made for a spectacular sight as you can see in Duluthian JeRay Johnson’s photo. The ship is now en route to the International Space Station.

Thursday morning, engineers filled its external fuel tank with super-cold liquid oxygen and liquid hydrogen, that when mixed, react explosively to create the thrust needed to counter Earth’s gravitational pull and send the ship into space.

A closer view of Discovery's liftoff west of the launch facility in Titusville by Jim Schaff, formerly of Hermantown, Minn.

Six astronauts will rendezvous with the International Space Station (ISS) to deliver supplies, spare parts, a new module for experiments and an external platform for large equipment. Oh, there’s one more passenger – Robonaut 2, a.k.a. R2,  the first humanoid robot to join the ISS crew.

Robonaut 2 surpasses previous dexterous humanoid robots in strength, yet it is safe enough to work side-by-side with humans. Here it's holding a 20-lb. weight. Credit: NASA.

R2, a joint project between NASA and General Motors, will become a permanent member of the space station. While NASA hopes to use the robot primarily to test its functions in the weightless environment of space, it’s hoped that one day R2 will be able to assist astronauts during spacewalks and provide help with other tasks.

This will be Discovery’s 13th and final trip to the space station. The sturdy bird has flown more missions than any other shuttle, logging nearly a year in orbit with an odometer reading of 143 million miles to prove it. When it returns, the ship will be decommissioned and most likely find a new home at the Smithsonian Air and Space Museum. One and possibly two more shuttle launches remain – Endeavour on April 19 and Atlantis on June 28. The Atlantis mission still awaits funding however.

The crew of STS-133 just before they climbed inside the Astrovan to go to the launch pad early this afternoon. Credit: NASA

Discovery will dock with the ISS around 2:16 p.m this Saturday the 26th. Over the next few nights observers across North America should be able to see the two craft approach one another as they follow one behind the other across the evening sky. The little game of cat-and-mouse is enjoyable to watch and photograph.

I’ll post the best times for viewing as well as tips on how to take your own photos in the coming days. Thursday night the space station will track west to east across the northern sky starting at 7:25 p.m. CST for the Duluth, Minn. region. Friday evening it will pass directly overhead at 6:18 in a bright twilight sky followed by Discovery at 6:43 halfway up in the northern sky. For times for your town, click HERE and enter your zip code.

Slightly more technical but very up to date is NASA’s Human Space Flight website. Once you key in your zip code or select your city from a map, a window opens up with ISS as the default satellite. Open the menu and scroll down to select SHUTTLE. Click the NEXT SIGHTING button to get evening passes visible from your town.

The last quarter moon will be about three degrees from Antares tomorrow morning before dawn. Created with Stellarium

Planning on being out tomorrow morning before dawn? Take a look at the last quarter moon. Just a few degrees to its right, you’ll see Antares, the brightest star in the constellation of Scorpius the Scorpion outlined in the map at right.

Last quarter phase is also a good time to spot craters along the moon’s centerline or terminator using a pair of binoculars.

Man in the moon’s smile still fresh after 172 years

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The first photo was taken of buildings and a courtyard outside the photographer's second floor study window in 1826. Sunlight illuminates both the left and right sides of the picture because the exposure lasted 8 hours. Credit: Joseph Niépce

Photography, which has been around for nearly two centuries, is constantly reinventing itself. Who could have guessed 20 years ago that telephones would do double duty as cameras?

The first photograph was made in 1826 by French inventor Joseph Ni̩pce. He used a pewter plate coated with a tarry substance that hardened when exposed to light and took a picture looking outside an upstairs window of his courtyard and out-buildings. The exposure lasted nearly an entire day Р8 hours!

Niépce then washed away the soft, unexposed tar, coated the hardened parts with ink and made an impression on paper to create a positive print of the scene. It wasn’t long before new, more efficient processes were developed, including the practical daguerreotype, invented in 1839 by another Frenchman, Louis Daguerre.

Here a thin coating of silver was applied to a copper plate and then exposed to iodine vapor, which converted the silver to silver iodide, a compound sensitive to light. A lens focused the image onto the plate, an exposure was made, and the photographer ‘developed’ the image with mercury fumes.

One of the first, if not THE first astrophoto ever taken. It was taken by John Draper sometime in the winter of 1839-40.

While the process may have been ruinous to your health, exposures were shorter and  images much sharper. The same year the daguerreotype was invented, John W. Draper, an American physician and chemist, used the process to take the very first successful photographs of a celestial object – the moon. Daguerre himself made a slightly earlier attempt but the picture was dark and not properly exposed.

Draper, at right, worked throughout the winter of 1839-1840 to get a clear lunar image using a telescope atop his rooftop observatory in New York. He finally succeeded with a 20 minute time exposure which produced an image only 1″ in diameter. The first pictures look crude to us today, but they clearly show the lunar seas (dark spots) and craters.

Psychedelic light show? No, it's a picture of the last quarter moon by John Draper probably taken on March 26, 1840. The moon is the white "half a pie" inside the dark circle. Courtesy: New York University

From there, astrophotography took off as astronomers quickly realized the camera could record a scene more faithfully and in greater detail than the eye. Longer time exposures and more sensitive film emulsions also meant a camera could see fainter stars, galaxies and nebulas entirely beyond the reach of the eye.

How quaint to think that prior to photography, astronomers sketched what they observed. The pencil was king! In the 20th and 21st centuries, professional astronomers almost never look through a telescope. Precious light from distant stars and galaxies is funneled through light-sensitive chips and stored on hard disks for later study.

Cameras have gone into space as well. Astronauts have packed them aboard orbiting spacecraft and all the way to the moon. Robotic spacecraft have carried the art of photography across the solar system.

The composite map of the moon was compiled using images from the LRO. Click to enlarge. Credit: NASA

As a demonstration of how far we’ve come since Draper’s time, I leave you with this amazing composite photo of the moon. It’s a mosaic of 1300 images taken over the course of two weeks last December by the Lunar Reconnaissance Orbiter (LRO). It looks a little different from the bright, flatly-lit full moon we’re accustomed to, because the orbiter took photos with the sun off to one side or the other in order to show lunar surface features with greater clarity.

For hours of free lunar fun, click on over to the full resolution image, where you can zoom and pan your heart away around the entire nearside of the moon. What a journey it’s been since that chill winter of 1839.

Amateur astronomers record probable lunar impact

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The northern lights put on a great show south of Tromsø, Norway last week. Details: Canon 5D Mark II, 14 mm lens at f/2.8, ISO 2500 and 2-second exposure. Credit: Ole Salomonsen

While observers in the northern U.S.  and southern Canada have seen little to no northern lights in the wake of recent solar flares, that hasn’t been true for people living in the Arctic north. This photo is proof of that. It was taken on Valentine’s Day near Tromsø, Norway, the aurora capital of the world. Although the moon was out at the time (upper left), it did little to compromise such a beautiful picture. In fact, the sparkle it added to the snow in the foreground gives us a feeling of really being there. Click HERE to see more of Ole’s aurora photos.

A likely meteorite hitting the moon caught on video on February 11. Credit: Stefano Sposetti

Last week the online lunar studies magazine Selenology Today reported that two European amateur astronomers simultaneously detected a probable meteor impact on the moon on February 11. Stefano Sposetti and Marco Iten, both of southern Switzerland, were monitoring the earth-lit portion of the crescent moon through their telescopes. Each captured the sudden flash along the moon’s dark limb on video around 9:37 p.m. local time.

No word in how large an object created the flash, but judging from its brightness, it must have been at least a few inches across. In other words, a nice-sized rock.

The small spot at left shows the location of the observed impact along the extreme western edge of the moon. Credit: courtesy Selenology Today

We’re used to hearing about the occasional meteorite landing on Earth, but don’t often consider the same happens on the moon.

Most meteors burn up as they’re seared by our atmosphere. If not, the air reduces a meteor’s speed from around 50,000 mph to no more than that of a rock tossed off a tall building. It lands with a hard smack, but unless a meteorite is substantial, most don’t make craters and only monster ones vaporize on impact.

The moon is different. Even though it’s smaller and has less gravity to pull on incoming space rocks, it lacks an atmosphere to slow them down. Meteorites hit the moon’s surface at their original cosmic velocities of dozens of miles per second. Many vaporize on impact – the flash you see in the video – and gouge surprisingly large craters for their size. Even a rock as small as five inches across can make a crater 10 feet in diameter. The meteorite’s energy comes from its speed, which converts it into a powerful, rock-excavating machine on impact.

The first meteor seen to strike the moon was in 1999. A handful of others have been recorded since.  Scientists are very interested in how often meteorites strike the moon because if we ever send astronauts back there to build a permanent base, we’ll have to consider where and how to build to safely avert the occasional meteorite. My suggestion: underground.

Depth and perception in the solar system

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Saturn, Spica and the moon late tonight in the southeastern sky. Created with Stellarium

Tonight the moon rises around 10:45 p.m. in the southeast, but if you wait until 11:30 or so, you’ll get to see it lined up “single file” under Spica and Saturn. The moon will be about 4 degrees below Spica and double that distance from Saturn. If you’ve been having difficulty finding Saturn, let the moon give you a hand this evening.

Another interesting if invisible series of lineups or conjunctions are happening near the sun today in the daytime sky. Mercury, Mars and Neptune are gathered together only a few degrees west of the sun.

Solar glare and the bright blue sky make this event impossible to see here on Earth, but from the Solar and Heliospheric Observatory (SOHO) in space, it’s a no-brainer.

This photo of the sun and planets was taken by the SOHO coronagraph on the 19th, when the planets were nearly lined up. I've drawn a circle indicating Neptune's location, since it's just a tad too faint to show. The short streaks are caused by cosmic rays striking the image sensor. Credit: NASA/ESA

SOHO studies the sun’s outer atmosphere, called the corona, using a coronagraph with an occulting disk that covers the sun and block its glare. That way it can get in close enough to study the movements of hot gases that compose the corona. The field of view of the coronagraph is large enough to include numerous background stars as well as the occasional comet or planet that wanders by.

If we could float above the plane of the solar system, we'd see that Mercury, Mars and Neptune are at vastly different distances from Earth. But from the point of view of an Earth-bound observer (black arrow), they appear to be lined up near one another in the sky. The numbers stand for the planets' distances from our planet in millions of miles. Solar system not to scale. Illustration: Bob King

Mercury, Mars and Neptune all lined up under one or another yesterday and today for a series of three conjunctions. Planetary alignments give us the opportunity to understand the layout of the solar system. They’re also are a reminder that our inability to perceive depth in the sky creates the illusion that celestial objects are close to each other when most of the time they’re not.

You can use this understanding when you go out to see the moon-Spica-Saturn lineup tonight. In that situation, the moon will be much closer to us than Saturn. Saturn in turn is much, much closer than Spica, which glimmers at a distance of 250 light years or some 1,500,000,000,000,000 miles. That’s 1.5 quadrillion miles. Yikes, I think we’ve gone far enough.

Space station returns to view in time for Discovery rendezvous

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Space shuttle Discovery stands at Launch Pad 39A at NASA's Kennedy Space Center following its rollout from the Vehicle Assembly Building. Photo credit: NASA/Kim Shiflett

The space shuttle Discovery is scheduled to launch at 3:50 p.m. Central time this coming Thursday. Some three and a half months ago, Discovery was grounded because of cracks in its external fuel tank Those have been repaired and the shuttle is ready to go.

The six-member crew plans to fly to the Kennedy Space Center today to begin preparations for the 133rd mission to the International Space Station (ISS).  They plan to deliver supplies, spare parts and a final U.S.-built module to the ISS. It will be Discovery’s last flight.

Timing of the mission couldn’t be better. The space station returns to easy visibility with a series of passes across the evening sky starting tonight. Later this week, we’ll hopefully have a chance to see both the shuttle and ISS play cat-and-mouse as they chase one another across the sky prior to rendezvous.

A time exposure of the a brief pass of the space station in March 2009. The ISS fades and disappears near the top when it enters Earth's shadow. Photo: Bob King

You can get warmed up for the fun by watching the ISS to pass over your house. It looks like a bright star moving in a west to east direction. Unlike an airplane, the station’s light is steady, not blinking, except on rare occasions when it catches the sun’s light just right. Then it can suddenly flare and grow as bright or brighter than Venus.

To find times to view the ISS from your town, log in to Heavens-Above and or go to Spaceweather’s flyby page and key in your zip code.

Readers with telescopes and a hankering for a real challenge can try spotting the space station through the eyepiece. Use low power to make it easier to catch, and aim the telescope a little ahead of where you expect the station to cross your field of view. 50x will show its distinctive H-shape created by the large solar panels.

Once you’ve got it in your field of view, keep watching, because the ISS will shrink in size as it moves off to the east. If you happen to be following it into Earth’s shadow, the view is even more dramatic as the ship changes color from yellow to deep red during orbital sunset.

Space station viewing times (Central Standard):
* Tonight starting at 7:16 p.m. Short pass in the southwestern sky
* Mon. Feb. 21 at 7:42 p.m. Another short one low in the west.
* Tues. Feb. 22 at 6:33 p.m. Fine pass across the southern sky under Orion.
* Weds. Feb. 23 at 6:59 p.m. Goes straight overhead and will be nearly as bright as Venus!
* Thurs. Feb. 24 at 7:25 p.m. Travels across the northern sky, disappearing in Earth’s shadow after passing under the North Star.
* Fri. Feb. 25 at 6:15 p.m. Another brilliant pass across the top of the sky in bright twilight.
* Sat. Feb. 26 at 6:41 p.m. A fine, bright pass across the northern sky.

Next door neighbor sunspot groups 1161 and 1162 have been active with flares this week. This photo was taken today at 10:30 CST.Credit: SDO/HMI

The sun’s still going to town with new sunspots popping up like pimples every day. The groups labeled 1162 and 1161 are complex and producing flares regularly.

Friends and I have been out looking high and low for northern lights from all the activity, especially the X2 class flare that erupted on Valentine’s Day. Nothing seen yet. For all we know, there have been minor auroras visible from the northern tier of states, but the moon’s lit up the sky so brightly, it’s hard to be sure. This week the moon will slide out of the evening sky as it moves into waning gibbous phase. Darker skies should make aurora-spotting easier.

Click HERE to read an interesting article on the effect of solar flares on our cellphones and other communications.

Are you ready for a Siriusly good time?

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Sirius is that unmistakably bright star shining in the lower half of the southern sky on Februrary evenings. Photo: Bob King

Sirius glinted off the ice on our rural road last night. At 8.6 light years away, it reminded me of what life was like 8.6 years ago, when texting didn’t exist and my children were still children. I like this star. I like how it scintillates and dances. How pure and white its light shines.

Sirius is the brightest star in the heavens. You can’t miss its beacon-like presence in the south in mid-February. At nightfall, the star is already well up in the southeast, reaching its highest point in the south around 9 o’clock. Here in Duluth, Minn., Sirius peaks at 25 degrees or a little more than two fists held at arm’s length at that time. In southern Arizona, it does much better, hovering some 45 degrees high or halfway to the zenith.

Stars are binned in brightness according to the magnitude scale, devised by the Greeks around 150 B.C. The brightest stars were said to be of ‘first magnitude’ while fainter stars were magnitude two, three and so on down to 6th magnitude, the faintest visible with the naked eye.

Sirius is the brightest star in the constellation of Canis Major the Greater Dog, here shown around 9 p.m. The dog's head is composed of fainter stars to Sirius' left, while his hind legs form a triangle at the bottom. Created with Stellarium

Magnitudes have been refined since ancient times. In particular, the scale now extends into negative numbers for the brightest of stars. The higher the negative number, the brighter the object. Sirius shines at magnitude -1.5 while its next closest rival, Canopus, visible in the far southern U.S., checks in at -0.7.

Here are magnitudes of some familiar celestial objects rounded to the nearest tenth:

* Arcturus — 0.0
* Vega — 0.0
* Spica — 1.0 or first magnitude
* Regulus — 1.4
* Alkaid (star at end of Big Dipper’s handle) — 1.9
* Jupiter around -2.5
* Space station around -3
* Venus around  -4.5
* Full moon -13
* Sun -27
* Faintest star seen by Hubble Space Telescope — 30

Sirius' tiny companion star orbits it at about the same distance Uranus orbits the sun. Credit: NASA/ESA

For most sky watchers in mid-northern latitudes, Sirius is outshone only by Jupiter, Venus, the moon, sun and the International Space Station. Sirius’ name comes from the Greek word for ‘scorching’, appropriate given its searing brilliance. It’s nickname, the Dog Star, is also fitting as it heads up the constellation Canis Major the Greater Dog. Sirius is a white star similar to the sun but almost twice as large and 26 times brighter. It spins on its axis once every 5 1/2 days compared to the sun’s 27 day period.

Though Sirius has celebrity enough, it’s nearly eclipsed in notoriety by its tiny companion, a white dwarf star slightly smaller than the Earth called Sirius B. Known informally as the ‘Pup’, the star orbits Sirius once every 50 years. At magnitude 8.4, it’s almost always lost in the glare of its brilliant sibling.

1891 photo of Alvin Clark, the first person to see Sirius B

What it lacks in brightness, the Pup makes up for in temperature and weight. Its surface cooks at 44,500 degrees vs. Sirius’ 17,500 degrees, and a sugar cube-sized chunk of its matter is so dense it weighs as much as an average-size compact car. Despite its size, Sirius B has enough gravity to tug on Sirius, causing it to wobble back and forth. The wobble was first detected by astronomer Friedrich Bessel back in 1844, but it wasn’t until 1863 until Alvin Clark, a famous telescope maker, first spotted it through his new 18 1/2-inch refracting telescope. He was testing the instrument at the time, pointed it at Sirius, and was surprised to see it accompanied by a faint companion. It was the first white dwarf discovered.

Sirius B will get easier to see in the coming decade as its orbit takes it farther from its much brighter sibling. Their separation varies between 3" and 11"; they're currently about 9" apart.

Amateur astronomers are looking forward to seeing Sirius’ companion this season and in the coming years. The two stars were closest and nearly impossible to separate in amateur telescopes in 1994. Since then, they’ve been opening up and can now be split in 3 and 4-inch telescopes with superb optics using high magnification in excellent seeing conditions.

I know, that’s a few caveats, but on the right night, it’s a worthy challenge and an opportunity to see a unique star.

If you’re game for a look, you can use the diagram to help you spot Sirius and its famous little sidekick. Despite numerous attempts, I’ve yet to see the Pup – mostly due to bad seeing from turbulent air – but I don’t plan on giving up anytime soon.