The moon and Spica tonight (June 30). While you’re out this evening, watch for purple-tinted skies during twilight from aerosols lofted into the upper atmosphere by the Sarychev volcano near Japan. More on this in tomorrow’s blog. Created with Stellarium

We’ve been hit big time here in Duluth by clouds, but if it’s clear by you this evening, take a moment to enjoy the waxing moon in the company of Spica, the brightest star in Virgo the Virgin. Spica is very close to the ecliptic, the path the moon, sun and planets travel along in the sky. This guarantees a regular monthly visit.

If Spica’s so close, how come the moon’s still so far away from it? It happens that the moon’s orbit is tipped relative to the Earth’s. If it were exactly flat and concentric to the Earth’s orbit, it would travel along that imaginary red line month after month, year after year, never varying. This week, the moon is near the bottom or most southerly point in its orbit at the same time it passes near Spica. That places it significantly further south of the star than usual. Matter of fact, the moon’s so low from the northern U.S., it hardly clears the trees around my house by nightfall. During a different month or year, the moon might be found right on the ecliptic, above Spica or even covering it up in an occultation.

That little tip sure keeps things interesting.

Map of Russia showing the approximate location of the Tunguska (tune-GOOSE-kuh) Event. Credit: Wikimedia

Exactly 101 years ago today at 7:17 a.m. local time, a trail of light brighter than the sun followed by several enormous explosions, rocked the air over the Tunguska River in Siberia and scared the living daylights out of the local reindeer herders. The blast flattened trees over an 800 square mile area but strangely, left no meteorites or crater. Sensitive barometers as far away as England recorded the sudden change in atmospheric pressure from the blast wave, while for several days afterword the night sky across Europe and Asia was aglow with strange, bright clouds.

Not until 1921 did anyone attempt to find out what happened that day. That’s when Russian mineralogist Leonid Kulik (left) put together an expedition to trek to the site of the explosion. The incredibly remote and difficult terrain put the kabosh on his first attempt but his second, in 1927, was successful.

The pictures show it all. Over 80 million trees were flattened, and those near the epicenter were stripped of their bark and limbs. Debranching without destroying an entire tree requires a shock wave similar to that in a nuclear bomb. Kulik photographed the landscape and described what he saw but could find no trace of what caused the damage.

A swath of trees that were flattened in a radial or circular pattern by the blast wave from the comet or meteorite that exploded in the air over Siberia on June 30, 1908. Credit: Leonid Kulik expedition

Another view of the flattened trees taken by Kulik’s discovery party. If the aerial blast had occured over a large city, it’s estimated 500,000 people would have died. Credit: Leonid Kulik expedition

While no one is certain exactly what caused the Tunguska Event, the most likely explanation is that an asteroid or comet, traveling at over 30,000 mph, detonated and annhilated itself some five miles up in Earth’s atmosphere due to the incredible pressures and heat on entry. The aerial destruction released the equivalent of 185 Hiroshima atom bombs. This would explain the explosion effects as well as the lack of a crater or meteorites. Interestingly, later expeditions into the region turned up tiny spherules of meteoric material in the trees and soil, possibly the dusty debris from the explosion.

Recent research now points to a comet as the likely culprit rather than a small asteroid. Asteroids are rocky while comets are primarily made of ice. What tipped scientists off were those reports of glowing clouds late at night. They are almost certainly noctilucent (noc-ti-LOO-sent) or "night shining" clouds, located 55 miles high in the atmosphere, far above most familiar weather clouds. They’re visible from the northern U.S., Canada and Europe, and appear very low in the northern sky near the end of evening or the beginning of morning twilight when all other clouds are dark.

Michael Kelley, the James A. Friend Family Distinguished Professor of Engineering at Cornell, who led the research team, compared the space shuttle’s exhaust plume to the water vapor that would be released by a comet striking the atmosphere. Kelley saw noctilucent clouds created by the shuttle flights in 1997, 2003 and 2007. A comet would have broken up at the same height as the water exhaust.

"It’s almost like putting together a 100-year-old murder mystery," said Kelley. "The evidence is pretty strong that the Earth was hit by a comet in 1908." To read more about the team’s research, click here.

I wish I’d been in a better location when I took this photo of noctilucent clouds last Friday morning. Too many trees! The display was extremely low in the northern sky around 3:15 a.m. Details: 200mm lens at f/2.8, 15 second time exposure at ISO 800. Photo: Bob King

Just the other morning I was out admiring Venus and Mars when I saw my first noctilucent clouds of the summer. They were very low in the northern sky around 3:15 a.m. some two hours before sunrise. Long summer twilights are the best time to watch for these elusive beauties. Look for delicate white tendrils stretching very low across the north when the stars begin to appear. Binoculars will help bring out the clouds’ intricate detail. Whether what you’re seeing is spent shuttle exhaust or a remnant of Tunguska, there’s magic in these strange clouds. 

The upper patch of dull color in this photo taken last week from Duluth is a circumzenithal arc touching part of a larger 46-degree halo. The inner concentric rings around the sun are a rare halo phenomenon caused by pyramid-shaped ice crystals in high cirrostratus clouds. Photo: Bob King

Last Wednesday as the sun dropped in the west, it was surrounded by a remarkable series of halos I’d never before seen. Most common halos are caused by light refracted or bent by microscopic, six-sided ice crystals that look like cut up pencils. Light enters one side of the crystal and is bent at a 22-degree angle as it exits the other side. All the millions of crystals together create a ring around the sun with a radius of 22 degrees.

This is the cropped and enhanced version of the halo pictured above. The sun is ringed by 9, 18 and 22 degree halos, a couple of which show color along their edges. Because pyramid ice crystals have many different faces at a variety of angles to one another, they can create multiple odd-dimension halos. Photo: Bob King

This halo was different. I first noticed a colorful patch, called a circumzenithal arc, well above the main halo. You’ll see in the photo that light continues on either side of the arc to form part of the larger, rarer 46-degree halo. What really caught my eye however were the several nested halos within the space between the sun and the normal 22-degree halo.

After a search through books and online sources, I discovered that these odd, concentric halos were caused by pyramidal ice crystals. In the contrast-enhanced picture you can count at least three of them near the sun.

What amazes me is that you can see hundreds of halos in your lifetime and still not see them all. The constant interplay of light and ice has surprises in store for both daytime and nighttime skywatchers. For more on this unusual phenomenon, you can visit this website.

I’m not the only one that’s been busy with their camera. We’ve also received some really nice photos from our readers in the past week. Here they are for you to enjoy. Thank you Lyle and Andrew for sending them.

The fair city of Duluth reflects on a calm Lake Superior last Thursday night. Photo credit: Lyle Anderson

The International Space Station cuts a path of light through the sky from Duluth’s Park Point Sunday morning. The little wiggle at the far left end of the trail was caused by camera movement, possibly the wind. At upper right, you can see the W of Cassiopeia. Photo credit: Lyle Anderson

The photo of lightning bugs last week inspired photographer Andrew Kirk of Bishop, Calif. to send this picture of colorful water trails. "Drops of water flung from a rushing mountain stream catch sunlight as they spin and distort. A single drop may rotate and reflect numerous times during its flight and even refract mini-rainbows back to the camera," Kirk writes. Photo credit: Andrew Kirk

Sarychev Peak erupts on June 12 in this photo taken from aboard the International Space Station. The plume is believed to be a combination of ash and steam while the smooth, white cloud at top is probably water condensation from rapidly rising air. Hi-res image. Credit: NASA

Although it’s not directly related with astronomy I thought you’d enjoy seeing this spectacular photo and video of the eruption of the Sarychev volcano in the Kuril Islands northeast of Japan. It was taken earlier this month by International Space Station astronauts and captures the early eruption of the islands’ most active volcano as well as a hole in the cloud deck that some scientists believe was caused by the blast’s shockwave. The video is a compilation of still images made by the orbiting astronauts. The best part comes near the end. For more on the eruption, see this link.

How about a few more amazing photographs? The following were all taken by the Hubble Space Telescope in 2009, which has been on the job now for 19 years. All images credited to NASA/ESA.

In 1987 a bright supernova exploded in the Large Magellanic Cloud, one of the Milky Way’s satellite galaxies. The shockwave of material from the blast slammed into gas shed by the star long ago, creating a ring of bright spots around the supernova. The ring is about a light year across. The pink object in the center of the ring is debris still glowing from the exploding star, while two stars lie on either side of the ring. Scientists still don’t know what causes the thin red arcs. Hi-res image.

How about this — two galaxies that form the number "10". This galactic duo is known as Arp 147. The galaxy on the left literally passed through the one on the right, creating a hole in it. The "fly through" also stimulated a wave a new star formation (blue knots) in the shape of a ring. Hi-res image.

The planetary nebula NGC 2818 in the southern constellation of Pyxis the Compass. The glowing layers and shell of gas were created when a star shed its outer layers into space after running out of nuclear fuel. The remainder of the star, called a white dwarf, is buried deep within the nebula and excites the shell to glow in spectacular colors. Hi-res image.

Ganymede, the largest moon in the solar system, ducks behind the limb of the planet Jupiter. Composed of rock and ice, the moon orbits Jupiter once a week. Also shown is the Great Red Spot, a weather system that’s twice the size of Earth. Hi-res image.

A composite color image made in infrared (heat) light by both Hubble and the Spitzer Space Telescopes shows the central 300 light years of the center of the Milky Way galaxy. Infrared light penetrates the dust the would otherwise block the view. We see massive wild loops of hydrogen gas sculpted by the winds and radiation of massive stars, and three clusters of giant stars called the Central cluster, the Arches cluster, and the Quintuplet cluster (the three bright knots). Hi-res image.

A compact group of three galaxies 400 million light years away in Virgo called Arp 274. The galaxies on the left and right sides are forming new stars at a high rate as revealed by the bright blue spots in their spiral arms. Hi-res image.

The International Space Station (ISS) shows as a trail of light as it passes over northern Minnesota Friday morning. This coming week the station will continue making mulitple passes over the U.S. during the early morning hours. Photo: Bob King

Summer nights are sure short. Back in the winter, the ISS would make passes over the region around 6 a.m., a time more of us were likely to be up and around. Now because of early sunrises, those flybys occur during the very wee hours of 2 and 3 a.m.

Still, if you happen to be up late, it’s nice to know you’re in the company of the astronauts. Here are times to spot the ISS in the coming week. Except where noted, all passes begin in the west or southwest with the station moving eastward across the northern sky. Look for a bright, moving "star".

Sun. June 28 beginning at 3:32 a.m. Brilliant flyby!
Mon. June 29 at 2:24 (appears high in the east) and 3:56 a.m. Earlier flyby a bright one.
Tues. June 30 at 2:47 and 4:21 a.m. "     "
Weds. July 1 at 3:10 and 4:46 a.m.
Thurs. July 2 at 2:02 and 3:35 a.m. "     "
Fri. July 3 at 2:25 and 4 a.m.
Sat. July 4 at 1:16 (appears due north), 2:49 and 4:24 a.m.  "     "


This map shows the sky as you look south about two hours after sunset when twilight has ended. The four "M" objects shown are all visible in binoculars while three of them, M8, M6 and M7 can even be seen with the naked from a dark sky site. Created with Stellarium.

The forecast may look bleak for tonight but soon the sky will clear again. When it does, I hope you can find a place with a wide open view toward the southern horizon because the richest part of the summer Milky Way awaits you there. When you look into the tail of the scorpion and further east into Sagittarius the Archer, you’re gazing toward the center of the galaxy. Though the center itself is obscured by countless clouds of cosmic dust, the entire region is thronged with globular star clusters, cloudy nebulas and open clusters. We’ve looked at a few of these over the past few weeks but now it’s time to unload the full cart of bananas.

A time exposure photo from two nights ago shows the same slice of sky as in the map above. I’ve added constellation outlines and the names of our featured binocular objects. The cloudy glow at left is the Milky Way while city light pollution lights up the lower right. Despite its low altitude from Duluth, M7 is easily visible with the naked eye. Both it and M6 are tucked are just above the scorpion’s tail. Photo: Bob King

All four of our featured deep sky objects start with the letter "M" because they were all cataloged more than two centuries ago by French astronomer and comet hunter Charles Messier. Since then, a few of the brightest or most distinctive-shaped ones have acquired nicknames. M8 is called the "Lagoon Nebula" because dark rivers of dust ply its nebulous confines. M7 goes by the "Butterfly Cluster" because the stars are arranged in a way that suggests the outline of a butterfly. 

You can make out the vertical bar of stars in the cluster M4 (left) and see one of the dark, dusty rivers in M8 (right). Globular clusters are highly compressed balls of hundreds of thousands of stars. Open clusters, like the little group of blue stars in the left side of M8, are looser. Photos: Jim Misti

So now that you have a good view southward and you’re observing from a reasonably dark place, point your binoculars at M4, a big globular cluster very near the bright star Antares (an-TAR-eez). Look for a softly glowing spot that looks totally unlike the sharp form of a star. M4 is a mere 7,200 light years from Earth and one of the closest globulars in the sky. That also makes it one of the few such clusters that you can resolve into individual stars in a small telescope. While you’re at it, look for one of M4′s peculiar features, a straight bar of stars that cuts vertically across its center.

M7 and M6 are both open clusters, which like the globulars, feel one another’s gravity and travel as a unit through space together. Unlike globulars, they’re much looser and contain far fewer stars. Open clusters are young groups of stars that hang out in the flat disk of the galaxy; ancient globulars reside in a great halo centered on the galaxy’s core.

The clusters M6 (left) and M7 in the constellation Scorpius. M6 is shaped like a butterfly while M7 looks like the letter K to me. Credit: M6 by Ole Nielsen; M7 by N.A.Sharp, REU program/NOAO/AURA/NSF

Two nights ago M7 was easy to see even though it was only a fist high in the south. It looked like a small chunk of the Milky Way. My 10×50 binoculars had no problem resolving much of it into stars. M6 is smaller, fainter and more star-like with the naked eye but an easy sight in binoculars. You’ll need a small telescope to see its remarkable butterfly shape. M6 is some 1600 light years away and about 25 light years across. M7 is about the same size but closer at 1000 light years.

That brings us finally to M8, a combination nebula and star cluster. The cloudy part consists of dust and gas that’s in the process of congealing into new stars. As if to prove the point, the little cluster embedded in the west side of the nebula was actually formed from material in the Lagoon. You can’t miss M8 in binoculars — it’s an elongated puffy spot with a bit of sparkle to it from the cluster.

Northern hemisphere summers have everything, from a million living things to the richest presentation of galactic treasures this side of Andromeda.

Venus and Mars rise up over the bog this morning around 3 o’clock. Venus is the bright "star" at right; Mars is just above it. The pair is very easy to see in early morning twilight. Can you find the Pleiades (Seven Sisters Star Cluster) in the photo? Details: 35mm lens at f/2.8, 20-second exposure at ISO 800. Photo: Bob King

Maybe some of you caught the feature on Minnesota Public Radio a while back about Wolfram Alpha, a computational website that’s attempts to "make all systematic knowledge immediately computable by anyone", according to its creator Stephen Wolfram. That’s lofty goal, I thought, and worth a look. The site currently has more than 10 trillion pieces of data and I can guarantee you’ll have fun when you get there.

For starters, put your first name in the search box and see what pops up. I discovered that "Bob" is a rare name these days shared by only 1 out of 3533 people in the U.S. "Bob’s" popularity appears to have peaked in the late 1930s and has been going downhill ever since. Aw, shucks. Jacob is currently #1 with 22,272 newly-minted users a year.

Want to know exactly how far Jupiter is from the Earth today? Type in "Jupiter" and you’ll not only learn it’s 36.28 light minutes away but all sorts of other things like size, number of moons and the layout of the four bright satellites at that particular moment. Got an equation and need an answer, or want to see how many digits of "pi" you can squeeze onto your computer screen? Wolfram Alpha (WA) can handle those and more.
 
I’m sure you can come up with all sorts of things to search, but before we wrap up, don’t forget to ask WA the following question: "What is the meaning of life?" You’ll appreciate the answer, especially if you’re a sci-fi fan.

Scorpius dominates the low southern sky this time of year. Find a place with a good horizon to see at least part of the scorpion’s tail. Created with Stellarium.

Late June and early July is prime time viewing for Scorpius the Scorpion. We’ve talked about this familiar zodiac constellation on a several occasions. Just look south at the end of evening twilight and find the bright, orange star twinkling there. That’s Antares, the Alpha or brightest star in the constellation. To the right are three stars aligned nearly vertically that form the head of the stinging arthropod. Those living in the northern U.S. don’t get to see the bottom of the scorpion’s tail because it’s cut off by the horizon, but if you live in Illinois or points south the entire tail is visible. The further south you go, the higher Scorpius ascends. I once saw the constellation from southern Peru, where it was so high I had to arch my back to take in the sight.

As we did with Cepheus earlier this week, try to familiarize yourself with as much of Scorpius as you can see from your location because tomorrow we’ll tour a few of its lovely binocular star clusters.

The Summer Triangle and Aquila as you’d see them at nightfall looking east.

At the same time as the scorpion creeps through the southern heavens, Aquila the Eagle flys high in the southeast. Altair is the bottommost star in the huge figure called the Summer Triangle, already well up in the east at nightfall. Two stars on either side, sometimes called the "Guard Stars" form the eagle’s head. The tail points off in the direction of the Milky Way. As long as you’re flying with the eagle, look one outstretched fist directly left of Altair and see if you can spot one of the neatest constellations in the sky, Delphinus the Dolphin. It actually looks like its shape. Or you might prefer to imagine the figure as a kite flying in the summer sky.

A 25-second time exposure photo from last night of Aquila (ACK-will-uh), Delphinus (del-FINE-us) and the star clouds of the Milky Way. The dolphin’s just a fist away from bright Altair. Photo: Bob King

The dolphin is rather dim but so compact and distinctive, it’s hard to miss. Telescope owners will want to point their instruments at the star called Gamma, which marks the dolphin’s nose (end star at the tip of the little diamond shape). Gamma’s a colorful, close double star 101 light years from Earth and one of the summer’s best known sky gems.

The mythological depiction of Aquila (eagle) and Delphinus (dolphin) from a 19th century star atlas. Credit: William Jamieson / Urania’s Mirror

The moon hangs between branches of a poplar tree yesterday during twilight. Details: 280mm lens at f/8, 1/15" exposure at ISO 800. Photo: Bob King

Did you see the crescent moon yesterday night in the west? It looked like a little rib bone hanging there in the pale blue of early twilight. Watch for the moon to line up with the star Regulus in Leo the Lion and Saturn tonight starting around 9:30 p.m.

Tonight (Thursday) the moon will point you to Leo’s brightest star Regulus and the planet Saturn. Regulus is not quite one outstretched fist to the upper left of the moon; Saturn is one fist to the left and above Regulus. Created with Stellarium.

Saturn is slowly edging toward the western horizon night by night and will disappear into the sun’s glare in August. You might recall that the gradual drift of planets and stars from east to west over the year is caused by Earth’s revolution around the sun. As we speed at 65,535 mph along our orbit, our view of what we see in the sky at night changes week by week, month by month. It’s like looking out the window of a car going down the freeway. At first we see our hometown but it gradually recedes into the distance, to be replaced by new cities and landscapes.
 
As Earth travels, the stars of summer rise in the east while those of spring set in the west. Since the Earth’s ‘freeway’ is circular, the pattern of seasonal stars repeats in a cycle year after year.

Saturn and its four brightest moons are shown tonight (Thurs.) as you’d see them in a 6-inch or larger telescope. Any telescope that magnifies at least 20 times will reveal Titan and the narrow rings. To find and identify Saturn’s moons at any time on any night, check out this cool applet. Created with Stellarium.

Right now, Saturn’s rings look like a thin pencil line through a small telescope but they’ll completely disappear when they’re exactly edgewise to the Earth on September 4. The reason they vanish in all but the largest telescopes is because the rings are incredibly thin for their size — many thousands of miles across but only about 30 feet thick. Sadly, the planet will be too near the sun for a good view of the disappearance. The same will be true for the next edgewise presentation in March 2025. Not until 2039 will we get to see Saturn ringless. Right now’s a great time to watch the rings narrow further as we approach September. 

Galileo’s telescopes were too crude for him to decipher Saturn’s odd appearance. It wasn’t until March 25, 1655, some 47 years after the telescope’s invention, that Dutch mathematician Christiaan Huygens (right) finally understood the rings for what they were.
In order to preserve proof that he was the first person to discover that Saturn was surrounded by a ring, he couched his announcement in code. It read like this:

aaaaaaa ccccc d eeeee g h iiiiiii llll mm nnnnnnnnn oooo pp q rr ttttt uuuuu.

But when all the letters were properly arranged in a Latin sentence, it read more like this:

"Annulo cingitur tenui, plano nusquam cohaerente, ad eclipticam inclinato."
 
or in English:
 
"It (Saturn) is girdled by a thin flat ring, nowhere touching, inclined to the ecliptic."

Huygens did indeed get credit for this discovery as well as the discovery of Saturn’s largest moon Titan. In our lifetime, his name became famous once again during the Cassini mission to Saturn. On January 14, 2005 a probe with his name on it landed safely on Titan and sent back the first-ever images of its icy surface.

Photos of ice rocks and boulders on the surface of Titan taken by cameras aboard the Huygens probe. Liquid methane probably flowed through the drainage channels in the photo (above left) taken while Huygens parachuted to the surface. Credit: NASA

A cumulominbus thunderhead is lit from within by lightning as it slowly floats in front of the stars of Sagittarius last night. Details: 150mm lens at f/2.8, 15 second time exposure at ISO 1600. Photo: Bob King

There were mosquitos everywhere but I found myself falling in love with summer. Silent explosions of lightning flashed along the south shore of Lake Superior last night. Astronomically speaking, the thunderclouds moved through eastern Sagittarius toward Capricornus. Although they later disappeared over the horizon, their lightning lit up the sky in sudden blasts until well past midnight.

Fireflies, mostly males, leave trails of light as they dance over the dark landscape Tuesday night. The stars left trails during the long time exposure; the bright one at top left is the planet Jupiter. Details: 70mm lens at f/2.8, ~3 minute time exposure at ISO 1600. Photo: Bob King

Even in twilight, the fireflies’ quieter lights dotted the fading contours of the landscape. By nightfall, they were thick. Their passion knew no bounds. Attracted to my flashlight, I had to repeatedly brush them off my sleeves. What the photos don’t show are the mosquitos that did their best to unnerve me as I pushed the telescope from comet to cluster to galaxy. After a half hour I stopped paying attention to the whine of their wings and enjoyed the night.

Very late I took off my coat and let the warm breeze and the terrific smells it carried take me away. Winter seemed as far as Antarctica. The hardest thing to do was go to bed — all I wanted was like a little kid to stay up all night.

With the new LCROSS mission (see yesterday’s blog) in the news lately, I thought you’d enjoy seeing the final footage from the Japanese Kaguya (KAH-goo-ya) spacecraft before it plunged to the lunar surface. As it moves ever closer, the view becomes ever more dramatic.

The lunar LCROSS mission reached its first milestone earlier today when it swung by the moon to help shape its orbit for an eventual rendevous and impact with that body on October 9. I came across two excellent videos that depict the mission, the unusual orbit and how the impact will happen. The beauty is that they describe everything visually without narration.

Click here for the full show from takeoff to impact or here just to see the orbit and impact sequence. Be patient and allow a little time for the videos to load. I think you’ll really enjoy them, especially the longer one which has a memorable soundtrack. If you’d like to read a synopsis of the mission and select the videos on your own, here’s the general website.

The crescent moon is shown for tonight (Tues.) and tomorrow. You’ll find it emerging from evening twilight over the next few nights. Maps created with Stellarium.

 Not only did LCROSS have a close lunar encounter, so will we if the sky is clear. The thin crescent moon returns to the sky during early twilight this evening (Tuesday). Look very low in the northwest direction a half-hour after sunset. By tomorrow evening, the moon will have swung up and away from the horizon far enough to view more easily.

While you’ll need a big scope to find Pluto, you can certainly picture it in your mind’s eye just above the Teapot of Sagittarius. For a detailed telescopic locator map, click this link. Our map shows the sky looking south around 11:30-midnight in late June.

Today the dwarf planet Pluto is at opposition. Opposition means just what it sounds like — Pluto will be directly opposite the sun in the sky, rise around sunset and remain visible all night. Of course ‘visible’ means different things to different people. Although Pluto will be at its closest to the Earth and brightest for the year, the planet is always very faint. You’ll need at least an 8-inch telescope and a very good star chart to find it. The planet is just a speck of light lost among the stars of the Milky Way in Sagittarius the Archer. It’s only 14th magnitude or almost 400,000 times fainter than Vega in the Summer Triangle.

Although this is not to scale, it does you an idea how far out there Pluto is. Today both Earth and Pluto are at opposition, another way of saying that both planets are lined up on the same side of the sun and closest together for the year. Pluto is quite small, only about 1430 miles across, just a little bigger than the moon (see below). Illustration: Bob King

At 2.9 billion miles from the Earth, a light beam or radio signal leaving our planet takes just over four hours to arrive at Pluto. For a fun little experiment, stay up late and point a flashlight in the planet’s direction before you go to bed tonight. By the time the robins are singing at dawn, perhaps a photon or two of your beam will have finally arrived at the frozen orb.

Since Pluto takes 248 years to complete one orbit around the sun, it moves very slowly through the zodiac. That means that once it enters a constellation it stays there a long time. Having just crossed the border into Sagittarius, Pluto will chill out with the archer for 16 years. For comparison, Jupiter spends about one year in each zodiac constellation, Saturn 2-3 years.

Pluto was the mythical Roman ruler of the underworld. On these warm summer nights, consider spending a few moments in his freezing presence.

Beginning in high school and continuing to this day, my friend Rick and I have done a lot of camping in northern Wisconsin, the Northeast and in the Southwestern deserts. During the early days we used his leaky pup tent, a low, triangular affair with a pole on either end held up by a lengths of rope and staked along the sides. Unlike the military version, ours had a floor. This simple shelter was a staple of camping for many years ago.

To find dim Cepheus (SEF-ee-us) you can use either the Big Dipper or Cassiopeia, both of which are very distinctive. This map shows the sky as you look due north in late June. Maps created with Stellarium.

I think of that tent and those many adventures when I look at up the constellation Cepheus the King this time of year. You can find Cepheus one of two ways — either by facing north and looking directly above the familiar W of Cassiopeia, or by using the Pointer Stars of the Big Dipper to first arrive at Polaris, the North Star. Cepheus is a one outstretched fist to the right of Polaris. It’s about the same size as Cassiopeia but has no bright stars, only modest ones a level fainter than those that compose the Big Dipper.

Cepheus pivots around the North Star during the year, constantly changing its orientation in the sky. In June and early July it sets up just like an old-fashioned pup tent. The star Gamma is nearest to the North Star and remarkable because it’s one of the brightest stars you can see that has a planet in orbit about it. Just look at Gamma the next clear night and in your mind’s eye imagine a planet some 45 light years away with 1.6 times the mass of Jupiter, orbiting about the star once every 2 1/2 years. It may even have cloud belts like our own Jupiter or perhaps a splendid set of nested rings like Saturn. Gamma Cephei b, as it’s called, was first suspected in 1988 and confirmed in 2002.

Use this closeup map to help you find our three featured stars in Cepheus. Gamma is an easy naked eye star while the others are plain to see in binoculars. Hint: their orange color give them away. The star Xi is a superb double star for small telescopes. VV and Gamma are also double but much too close to split. For help in pronouncing star names, many of which are identified by Greek letters, be sure to check out this website. Clicking on a letter there will pop open a sound file. 
 
While it’s well and good to imagine something you can’t see, Cepheus also has a few naked eye and binocular gems you’ll want to check out. Toward the back end of the pup tent is a star called Xi, pronounced ‘k’SEE‘, and next to it is one of the largest stars in the entire galaxy, VV Cephei (SEF-ee-eye). Since it’s 5th magnitude — 3 orders fainter than the Dipper stars — you’ll need dark skies to see it with your naked eye. Just use binoculars and look for an orange star at the position shown on the closeup map.

VV (shown at right) is a red hypergiant 3000 light years from Earth and one of the largest stars in the galaxy. Measuring 1,600-1,900 times larger than the sun, this big orange balloon of a star is well more than 1.5 billion miles across. Put in place of the sun, it would extend out nearly to the planet Saturn.

Nudge your binoculars one field to the right of VV and you’ll happen upon yet another orange-red star. This one’s called Mu but better known as the Garnet Star, which refers to its colorful hue. Mu is a little brighter and closer (2,400 light years) than VV and by remarkable coincidence almost as big — about 1400 times the size of the sun. The Garnet Star is a red supergiant and while it might seem rather lost among faint stars, in reality it’s one of the brightest in the Milky Way galaxy. Only great distance makes it appear ordinary.

VV Cephei, which could hold more than a billion stars the size of our sun, is so large it would absorb every planet out to Jupiter if placed at the center of our solar system. Credit: ElPeski

While a pup tent is decidedly a small, low-tech shelter, the one in the sky manages to house some of the most amazing stars in the galaxy. Try to familiarize yourself with Cepheus in the next week because we’ll be stopping by again to look at more of its wonders.