Back in April we looked at the sky’s most famous double star, the pair of Mizar and Alcor in the bend of the Big Dipper’s Handle. They’re still out and make a good place to start for some summer star splitting. Most people find it relatively easy to split the two. First locate the Big Dipper high in the northwestern sky after 10 o’clock. Now stare directly at Mizar, the brighter of the two stars. Just above it you’ll catch sight of its fainter companion, Alcor.

If you can split these two, you’re ready for a much more challenging pair in the constellation of Lyra the Harp. Lyra is one of the three constellations that comprise the Summer Triangle.

First find Vega, Lyra’s brightest star. Face east around 10:30 p.m. and look way up high, about six outstretched fists above the horizon. Vega is the standout, bright white star. You can’t miss it.

Vega is high in the eastern sky during late twilight. Look for a faint star to the left of Vega. That’s Epsilon. — created with Stellarium

 If the sky is dark enough to see the little parallelogram of four faint stars that form the harp, you’re ready to find our double star challenge, Epsilon Lyrae. Epsilon lies just to the left and slightly below Vega. At first glance, it’s a dim, ordinary star but point your binoculars at it and you’ll easily split it into a neat little pair of pearls — Epsilon 1 and Epsilon 2. 

Epsilon, while dim, is easy to find next to the bright star Vega in Lyra. The inset shows
a high power view of Epsilon in a 3" telescope. Each of the Epsilon stars is double again. — Illustration by Bob King

Now the challenge. Can you split Epsilon 1 and 2 with just your naked eye? It’s more than three times closer than Mizar and Alcor. First thing to do is get in a relaxed position. I recommend a lawn chair or just laying on the grass. Once again, stare directly at the star and concentrate. Can you see two yet — one to the upper left, the other lower right?

I’ll never forget the first time I split them. My daughter Maria and I were huddled together on the ground next to a campfire we built on a trip to the Boundary Waters. It was mid-August and the night was getting cold under a pitch black sky. Lyra was overhead so I asked her if she could split Epsilon in two. Her young eyes had no problem. She correctly told me their positions. Well, what the heck. If she could see it that easily, maybe I could. With some effort, I finally saw the two dim points of light nestled together like close-set eyes.

Epsilon Lyrae holds an additional surprise. If you look at it in a small telescope at around 200x, each star is double again! This has earned Epsilon the nickname "The Double Double" among amateur astronomers. On a calm night, the two close, ant-like pairs are nothing short of stunning.

Epsilon is about 162 light years away. The Epsilon 1 pair revolves around one another in 1,200 years, while Epsilon 2 takes 585 years. The two pairs also orbit about each other’s center of gravity in an achingly long time — about half a million years.

The moon visits the Pleiades tomorrow morning June 30 at dawn — created with Stellarium

The weather forecast calls for clear skies tonight. Ideal for splitting Epsilon Lyrae.  For the even more adventurous, the moon will tickle the Seven Sisters star cluster (Pleiades) tomorrow morning (June 30) at dawn. Face northeast in the early dawn light to find the delicate crescent moon. The Pleiades will be just to the moon’s right. I think this pairing will be most enjoyable through binoculars and a great way to start the day. 

Imagine what the sky would look like with the Earth out of the way. If you were an astronaut, say, somewhere between the Earth and moon, it would be easy. Since most of us have to remain on the planet, we’ll have to find another way. That’s where a planetarium-style computer program can help.

An all-sky view of the Milky Way in late June around midnight. — created with Stellarium

From dark, rural skies, summer is the best time to see the Milky Way in all its glory. The softly luminescent band of textured starclouds arches from the northeast to southwest after twilight’s end. A telescope will begin to resolve the chunky glow into countless individual stars and star clusters. All told, our galaxy contains at least 100 billion stars and perhaps as many as 700 billion. Most are so far away, their light blends into one continuous glow.

Remove the Earth and without the ground blocking our view, we can see the Milky Way full circle. — created with Stellarium

Now let’s remove the Earth so the horizon doesn’t get in the way. From our new perspective in space, we see that the Milky Way is really a complete circle of fuzzy starlight. All the constellations are visible at once — Orion, the Southern Cross, Big Dipper and the Summer Triangle. To take in the whole picture without seriously twisting your neck, you’d have to give yourself a gentle spin one way and then another with your handy jetpack.

If we could rocket above the galaxy and view it from above, we’d see that the sun is in a spiral arm well away from the galactic center. The sun takes a 1/4 billion years to go once around the center. Credit: R. Hurt/JPL-Caltech/NASA

From our horizonless perspective, you may wonder why the Milky Way is a circle? Why doesn’t it just fill up the whole sky? Our galaxy is shaped like an enormous flattened disk. When we direct our gaze through the disk — in the direction of the black arrows shown above — we encounter stars in every direction, the full 360 degrees. All these billions of stars stack up in the deep distance to create a thick, unresolved haze in the form of a circle. Our local horizon back here on Earth cuts off part of that circle, leaving us with the familiar band of the Milky Way we see at night.

A side or edge-on view of the Milky Way galaxy. Notice how thin the galaxy is compared to its width. When we gaze above or below the disk we see far fewer stars. Credit: NASA/COBE

However, if we look above or below the galaxy’s disk, we see only a scattering of nearby foreground stars and then lots of empty, intergalactic space. No more Milky Way band. This is the rest of the "ordinary" nighttime sky with familar constellations like Ursa Major, Orion, Bootes and Virgo that reside away from the Milky Way band.

Treat yourself to a drive in the country in the coming week before the moon returns to brighten the sky. Go out late, and see the great galactic disk for yourself. While you’re standing there, try to imagine the Earth dropping away beneath your feet to reveal the full circle of our galaxy.

Yes, you belong to something grand.

Crepuscular rays from the low, evening sun last week over Rice Lake Township — Bob King/Duluth News Tribune

We’ve all seen them — those rays of sunlight or moonlight bursting through openings in the clouds. They look positively heavenly. They’re called crepuscular (kree-PUSS-cu-lurr) rays because they usually make their appearance during the crepuscular hours of dusk and dawn.

Sunlight reflecting off airborne dust creates the bright rays. The dark rays are the shadows of clouds blocking the sunlight. The combination of light and shadow can produce spectacular fans of radiance that make even the life-weary stop and take notice.

Railroad tracks appear to converge in the distance — Photos.com

Although the rays appear to focus right back on the sun in a sort of corona, they’re actually almost parallel to each other. Think of railroad tracks stretching into the distance. They appear to nearly touch but of course never do.

Crepuscular rays are a common phenomenon — especially in the summer — and another aspect of our atmosphere that makes it a pleasure to be outdoors. Heavenly light serves as a perfect prelude for a night under the stars.

Tonight June 27 we’ll have two good Iridium satellite flares in the Duluth-Superior, Cloquet, Two Harbors, Iron Range region:

* Iridium 28 at 10:41 p.m. two outstretched fists high in the west — brilliant!
* Iridium 37 at 11:58 p.m. four fists high in the southwest — bright

Microscopic view of the soil sample nicknamed Rosy Red, retrieved by the robotic arm aboard the Phoenix on June 20. It was recently cooked in an oven and analyzed within the lander. The color is just the way you’d see the soil if you could bring a scoop to Earth. Credit: NASA/JPL-Caltech/University of Arizona/Max Planck Institute

If you haven’t already heard, the Mars Phoenix lander has been cooking up the soil sample retrieved from the Martian surface. Scientists have now found that it contains a variety of different salts. That means that it was once in contact with water. "This soil appears to be a close analog to surface soils found in the upper dry valleys in Antarctica," according to Phoenix co-investigator Sam Kouvanes of Tufts University. You can read more about the findings here.

Fireflies swoop and swerve beneath the beacon of Jupiter last night June 25. Photo taken with a 28mm lens at f/2.8, ISO 1600, 1-minute time exposure. — Bob King/Duluth News Tribune

Wow, the fireflies were spectacular last night. I had planned to look at any number of deep sky objects in the telescope but spent the first hour photographing shifting constellations of earthly stars instead. The males are the fliers, performing a mating dance to attract the attention of the females, who remain on the ground. Each firefly species has its own unique dance moves. I noticed wiggly paths in the shape of the letter "J", upward spirals and my favorite, the rapid Morse code-style flash. If a female is interested, she responds with a welcome flash.

Portrait of Saturn, Mars and Jupiter during twilight last night with some creative help from the fireflies. Same setup as above but ISO 400, 30-second exposure — Bob King/Duluth News Tribune

Fireflies are actually beetles, and they create their light by combining oxygen from the air with two chemical compounds in their bodies called luciferin and luciferase. Talk about efficiency, firefly light is over 90% efficient as compared to a incandescent light bulb, which uses 10% of the electricity for light while the rest dissipates as heat.

I finally sat down at the scope and perused the globular cluster M4 in the Scorpion (did you get to see it too?), some puffy nebulas and Jupiter. Twice in the middle of observing the deep sky, the surprise of seeing a brilliant green flash through the eyepiece nearly knocked me off my chair. Just a little firefly fun don’t you know.

If you’d like to learn more about lightning bugs or fireflies, check out these links.
* The Basics
* More Depth
* Bioluminescence

When my daughters were younger, one of their favorite books was about a hunt to find a bear in his cave called We’re Going on a Bear Hunt. To get there you had to surmount obstacles like muddy ground, a snowstorm, and tall grass. We finally found the bear in the end but got so scared we ran back home as fast as we could. It felt good to be safe again.

Small telescope view of Jupiter’s moons. The biggest and brightest moon, Ganymede, lies to the right or west of the planet tonight June 24. Jupiter is the brilliant "star" low in the southeast from 11 o’clock on. A pair of steadily-held binoculars will reveal the moon as a small "star" next to the planet. A small telescope will resolve the other three.

Ganymede, Jupiter’s largest moon, should put on a good show tonight in 7x-10x binoculars. It’s often referred to simply as III (as in Roman numeral III), and is the third of Jupiter’s four brightest moons. If the sky stays clear, why not give it a try. If you own a small telescope, you’ll see the remaining three moons clustered together on the other side of the planet as well as two dark "tire tracks" crossing Jupiter’s face. These are the two main equatorial cloud belts. A time lapse movie taken by the Voyager I spacecraft  in 1979 (below) shows just how active Jupiter’s atmosphere is. 

The big swirly oval is the Great Red Spot. It lies along the edge of the south equatorial belt and is three times larger than the Earth.

Jupiter as seen by Voyager 1 as it closed in on the planet in 1979.
One frame was taken every 10 hours to create a time-lapse movie. — NASA/JPL

Many years ago I was hiking in the Sonoran desert in southern Arizona. I love bare rock and the plants and animals that tough it out in arid climates. It was extremely hot that afternoon so I sought shade. A shadow created by two large boulders nearby looked inviting. As I walked toward it, the quietude was suddenly interrupted by the sound of wind. Coming up from behind and headed my way was a dust devil, a funnel of moving air and dust. It blew right through me, providing a brief but refreshing breeze.

Martian dust devil sequence recorded by the Mars Spirit Rover in May 2005 – NASA/JPL

When I saw these animated photos taken by the Spirit rover on Mars, I recalled my time in Arizona. Mars and Earth share many similarities including ice and icecaps, clouds, volcanoes, a similar day length (24 hours and 39 minutes for Mars) and seasons, to name a few. Seeing the same whirlwinds that are common in the Southwest make Mars that much more real.

Even though Mars’ atmosphere is 95% carbon dioxide, dust devils form the same way there as they do on Earth. The sun heats the ground, making it hotter than the air above it. Hotter air near the ground rises into the cooler air above, creating rising and fallling currents of hot and cool air. These develop into a swirling cell of wind that can pick up loose dust and sand.

Dust devil tracks crisscross areas of Mars’ surface in this photo taken by the Mars Reconnaissance Orbiter – NASA/JPL

If a big Martian dust devil blew past you in your spacesuit, you’d hear a ferocious pinging and scraping from the sand, but very little force of wind. That’s because Mars’ atmosphere is about a thousand times thinner than Earth’s. Martian whirlwinds come in all sizes but can be up to six miles high and a thousand feet wide with winds in excess of 70 miles per hour.

Moving sand and dust also create electrical charges. Scientists suspect that dust devils on Mars are riddled with tiny lightning bolts of static electricity from all that material rubbing together. If so, future astronauts will have to be careful to avoid them.

Back here on Earth, it’s no sweat. As summer kicks into high gear, I hope a cooling dust devil crosses your path.

My shoes are still damp this morning from wandering around the yard last night looking for a good spot to set up my tripod. Early on I wanted to photograph the two Iridium satellite flares. Jupiter beckoned later, and inspired me to carry the scope onto the lawn for a better view.

Iridium 33 flares last night June 22 in the Tail of Leo the Lion — photo by Tony Mitchell

Tony Mitchell of Duluth may also have grass clippings stuck to his shoes. He was out last night with a camera and tripod and sent along two fine images to share with our readers. You might recall we had two bright Iridium flares both in Leo in the nearly the same spot. Tony’s photo captured the Iridium 33 flare beautifully. 

The planet Jupiter puts on a good show even in the city — photo by Tony Mitchell

He also sent a picture of Jupiter the way many of us see the planet this summer — between houses and trees! Jupiter is in Sagittarius and nearly as low in the sky as it can get. Sometimes I feel like I’ve got to hop up and down to keep track of it. Thanks again Tony.

A corona around the moon last night June 22 caused by suspended pollen grains. I hid the moon behind the peak of a roof to more easily see and photograph it. Taken with a 200mm lens, f/4.5, ISO 400 and six-second exposure. — Bob King/News Tribune

The moon is now in waning gibbous phase and rose after 11:30 last night accompanied by another pollen corona. The inner disk was easy to see if you hid the moon behind a tree or roof. To see the outer disk, I had to look off to the side of the bright disk with the "corner" of my eye, rather than stare directly at it. The technique is called averted vision and works wonders for seeing faint details in low light.

Tonight Jupiter will shine brilliantly in the southeast after 11 o’clock while Scorpius rules the south. There are two more Iridium flares for viewing as well:

* Iridium 59 at 10:47 p.m. (tonight June 23) three outstretched fists high due west. It will be moderately bright.
* Iridium 8 is for night owls at 12:13 a.m. tomorrow (June 24) four fists high in the southwest. This one will be as bright as these flares ever get and should bowl you over.

Duck on its feet — Photo by Ian Britton/Freephotos.com

"It looks like a duck’s foot," my older daughter remarked after I pointed out the Head of the Scorpion to her the other night. And she was right. I’d never seen it that way before. That’s the way constellations are. You learn the "official" patterns but we somehow still make our way around by inventing little asterisms of our own.

Look toward the south around 10:30 p.m. tonight June 22 to find bright Antares. Use it to trace out the "duck’s foot" feature that represents the head of the scorpion. — created with Stellarium

Now that the moon has departed the evening sky, the zodiac constellation of Scorpius the Scorpion rears its head in a dark sky. You can see it starting around 10:15-30 p.m. Face south and look for the bright, red-tinted star Antares. Once found, it’s not difficult at all to see the three stars in a roughly vertical row to its right. If you take Antares and go the other way down toward the horizon, you’ll be working you way along the Tail.

From our latitude, the bottom of the Tail drags right along the horizon, but the Stinger, represented by the pair of stars very low in the southeast, does pop out of the haze. To see the entire scorpion, look during the midnight hour from a location with a clear view to the south. Scorpius is one of the few constellations that really looks like its name.

The Scorpion was sent by the goddess Artemis to sting Orion after he tried to have an affair with her. Another Greek myth claims it was sent to teach him a lesson after he boasted he could kill any beast. Either way, the two constellations are placed in opposite parts of the sky. As Orion sets, Scorpius rises triumphantly in the east.

While you’re out tonight, there are two treats awaiting you. We have back-to-back flares from two Iridium satellites. Both will be extremely bright. Here’s the info:

* Iridium 96 will flare at 10:41 p.m. three outstretched fists above the western horizon.
* Iridium 33 will be in virtually the same spot 12 minutes later at 10:53 p.m.

The times and direction are accurate for Duluth-Superior, Cloquet, Two Harbors and the Iron Range though the brightness might vary. Let us know if you have success in spotting them.

Small lumps of ice in the lower left corner of the trench (left image) taken on June 15
have disappeared by June 19 (right). There are other more subtle changes in the white material, likely ice, at top. Credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University

The ice chunks cometh! NASA released new photos yesterday showing small lumps of ice in one of the trenches dug by the robotic arm on the Mars Phoenix lander. Scientists know it’s water ice rather than frozen carbon dioxide (dry ice), because it would have otherwise disappeared in less than a day. The average high temperature at the site has been around 25 below zero.

Ice on Mars does not melt to form water and then evaporate. The temperature and air pressures are too low for that. Instead, ice goes directly from solid to vapor in a process called sublimation. Finding ice is great news for the scientists but even more important is what’s mixed in with it.

"The truth we’re looking for is not just looking at ice. It is in finding out the minerals, chemicals and hopefully the organic materials associated with these discoveries," said Phoenix Principal Investigator Peter Smith of the University of Arizona, Tucson. Scientists want to know whether the local environment around the lander has ever been favorable for the development of bacterial-type life. They’re looking for the organic compounds that might be its precursors. You can read more about it here.

Look low in the western sky during late twilight tonight June 21 to find the trio of
Saturn, the star Regulus and Mars. — created with Stellarium

The Summer Triangle commanded the eastern sky last night as it will for many weeks ahead. The area forecast is looking partly cloudy tonight so we might have a shot at seeing the gathering group of Mars, Saturn and Regulus low in the western sky around 10:30 p.m. Saturn is the brightest of the three and Mars the dimmest. Saturn is about three outstretched fists above the horizon at 10:30 p.m. Enjoy the evening.