Expect the unexpected when you step under the stars

The last quarter moon rises in a low fog beneath the little-dipper shaped Pleaides star cluster around 11:15 p.m. last night. Credit: Bob King

Fog can be magic. Like last night when the last quarter moon rose through the trees wearing a crown of foggy beams. The sight lasted only a few minutes until the moon rose higher and the mist moved on.

A low auroral arc with subtle banding glows in the northern sky last night. It’s topped by a faint, diffuse pink-purple band. Credit: Bob King

There are so many unexpected sights possible when you spend an hour or two under the stars. Auroras, meteors, the sounds of crickets mingled with the moaning calls of distant wolves. Even a few fireflies lingered last night.

A meteor streaks across the constellation aurora-steeped Perseus around 11 o’clock last night. Credit: Bob King

Despite some haze I checked out the planet Neptune in my pair of 8×40 binoculars. It was a dim “star” right where it was supposed to be. The nova in Delphinus still hangs in there at magnitude 6.1, right at the naked eye limit. A recent study based on the rate of decline in the nova’s brightness places the star at a whopping 13,000 light years from Earth. That’s farther than most of the stars we see on a clear night.

The northern hemisphere sky has no particularly bright comets visible at the moment. Famous (infamous?) Comet L4 PANSTARRS was a small, faint haze in my 15-inch telescope. Comet C/2012 F6 Lemmon continues to leisurely cruise across the high northern sky moving from Cepheus into Draco. It’s also a faint fuzzball but still shows a nice tail.

Comet Lemmon on Aug. 27. Its current brightness is around 10.5 magnitude. The amazing tail comes courtesy of Earth’s unique perspective on the comet at the moment. Credit: Rolando Ligustri

Earth is crossing the comet’s orbital plane this week so we see the comet and its debris cloud edge-on (in profile), giving Lemmon a remarkably long tail. The photo shows the true length; in the 15-inch scope only a fraction of the tail is visible, about 1 degree.

Step out the next time the stars are out and expect the unexpected.

Don’t let Comets PANSTARRS and Lemmon out of your sight … yet

Comet L4 PANSTARRS on May 18. The anti-tail extends straight out from the comet’s coma to the left. Use the map below to find the comet. Click to enlarge. Credit: Michael Jaeger

What the heck have comets L4 PANSTARRS and Lemmon been up to anyway?  Well, they’re still visible in 50mm binoculars and small telescopes. You can see them both sans moonlight in the morning sky after moonset. PANSTARRS first shows at nightfall not far from the North Star Polaris, one reason why it’s easy to find.

Map showing Comet C/2011 L4 PANSTARRS’ location tonight through June 21. Positions are marked off every three nights. Stars are shown to about magnitude 8. Credit: created with Chris Marriott’s SkyMap software

Shining at around 8th magnitude it looks like a fuzzy spot in binoculars, a bigger fuzzy spot with a brighter head in a small scope and a twin-tailed wonder in large amateur telescopes. It sidles up the Little Dipper in the coming month passing near that constellations two brightest stars – Polaris and then Kochab (KO-kab). Moonlight will soon compromise evening viewing but morning skies are still dark just before dawn.

Comet C/2012 F6 Lemmon on May 17 showing its short, diffuse dust tail (left) and long gas tail. Credit: Damian Peach

Michael Jaeger’s amazing photo shows how drastically different PANSTARRS looks compared to a month ago. The principle dust tail (off to the right and fanning left) so bright in March and early April has shrunk and faded. Meanwhile, the anti-tail, formed by dust trailing in the comet’s orbit, stretches at least a full binocular field of view to the left. PANSTARRS never ceases to amaze.

This map shows the sky facing east around 3:30 a.m. or approximately 2 hours before sunrise near the start of morning twilight. Comet positions are shown every 3 days; stars plotted to about 7th magnitude. Lemmon travels from Pegasus into Andromeda over the next month. Credit: created with Chris Marriott’s SkyMap software

Comet C/2012 F6 Lemmon has finally risen high enough before dawn to clear the horizon haze and treeline. At 7th magnitude, you can see in binoculars a more compact fuzzy spot than PANSTARRS; a telescope will show a faint, short tail to the southwest. Time exposure photos reveal a soft, rounded dust tail and long, skinny gas or ion tail.

Morning aurora topped off by avian cheer

A pretty series of rays sprouts above a pair of green arcs this morning around 3 a.m. CDT. Photo: Bob King

I got up for the stars but stayed for the birds. Clear skies overnight allowed for a look at a surprise aurora display, comets PANSTARRS and Lemmon, a handful of spectacular Eta Aquarid meteors and an attractive lunar crescent early this morning.

Three images from NASA’s Solar Dynamics Observatory were combined to create this spectacular view of last Friday’s flare. Credit: NASA

No auroras were predicted and true-to-forecast all looked quite at least through midnight. But at 2:30 this morning a bright green band spanned the northern horizon punctuated by one, two and occasionally an entire series of faint, rosy rays.

Sunspot group 1734′s largest spot – at left – is several times the diameter of Earth. This photo was taken this morning May 6, 2013. Credit: NASA

Expect more excitement courtesy of our parent star. Last Friday, a big flare erupted along’s the sun’s eastern edge, hurling a dragon-like tongue of incandescent hydrogen gas 120,000 miles (193,000 km) above the surface. Although this storm wasn’t directed toward Earth, the large sunspot group 1734 is currently nearly face-on to the planet and has the potential for strong flares. Cross your fingers.

A bright Eta Aquarid streaks across the northern sky and aurora this morning around 2:45 a.m. Photo: Bob King

I had planned to look at a variety of objects in the telescope but kept getting “distracted” by both the northern lights and regular appearances of incredibly fast, long-trailed meteors streaking across the northern sky from the east – Eta Aquarids.

Because the shower has a broad peak I encourage you to go out for a look yourself. Being so far north, I figured only a few might be seen here in Duluth, Minn. but was happily proven wrong. Had I simply sat in a lawn chair and stared skyward I’m certain I would have seen many more. Click HERE for more on the shower and how to view it.

A wide-field photo of Comet C/2011 L4 PANSTARRS shot on May 4, 2013. The comet is oriented the way it would appear shortly before dawn with the anti-tail pointing down and broad dust fan opening to the left. Credit: Joseph Brimacombe

Let me tell you about Comet PANSTARRS. In 10×50 binoculars I was surprised by how much there was to see under a dark sky. The V or fan-shaped tail spread is still obvious marked at its base by the small, brighter comet’s head. A second, straight anti-tail (debris left by the comet along its orbital path) stuck out like a pinkie finger from one side.

I estimated the whole works measured 1 degree or two full moon diameters across. While faint and smoky-looking at magnitude 7, the comet was very easy to pick out. In a 15-inch telescope PANSTARRS and its dual tails were brighter and better-defined; a tiny star-like nucleus peeped through the gases and dust concentrated in the its head. Very beautiful.

A morning topped off by the crescent moon is never wasted. Photo: Bob King

On to Comet Lemmon. I didn’t see it until 4 a.m. when dawn’s first light had already put its pale stamp on the eastern sky. I found it with difficulty in binoculars as a small, dim soft patch of light below the lower left star in the Square of Pegasus VERY low in the northeastern sky. It’s about as bright as PANSTARRS but low altitude and the onset of twilight combined to make it look fainter. In the scope, Lemmon was a big pale green fuzzball with a hint of a tail pointing southwest. Care to find it yourself? Here’s a map.

Wherever you are, enjoy the coming nights. If the moon’s your thing, an even thinner crescent will rise an hour before sunrise tomorrow in the east. Check for northern lights before you turn in tonight and use the map from yesterday’s blog to try your luck at Comet PANSTARRS … one last time.

 

Comet Lemmon’s back plus Earth may get peppered with Comet ISON dust

Comet PANSTARRS glides through the W of Cassiopeia at nightfall in late April. Look low in the northwestern sky about 1 1/2-2 hours after sunset to find it. Moonlight might render the comet invisible in binoculars, but a small telescope will still show it. This map shows the sky facing northwest around 9:30 p.m. local time. Created with Stellarium

As Comet PANSTARRS gallops off into the sunset of deep space, we anticipate the arrival of another fine binocular comet – C/2012 F6 Lemmon. Some of you might recall this comet from earlier in the year, when it reached naked eye brightness for sky watchers in the southern hemisphere and grew a long, ribbon-like tail.

After months of having it as their own, Lemmon will soon appear in the dawn sky near the Great Square of Pegasus at the end of this month in the northern hemisphere. Predictions indicate it might be visible with the naked eye from a dark, rural locale, but there’s no question we’ll see it in binoculars and small telescopes.

Comet C/2012 F6 Lemmon photographed through a 12-inch telescope from Namibia on April 21. Exposure time was 3 minutes. Notice the short dust tail and long, blue electrically-charged ion tail. Click to see more of Rhemann’s comet photos. Credit: Gerald Rhemann

Next week I’ll post a map and directions on how to find it. On May 6, a thin crescent moon will pass a short distance south of Lemmon, providing a helping hand. Comet PANSTARRS will still be out in May and though very faint in binoculars, a small telescope will show it.

I hate to go cometless for very long, so Lemmon’s arrival is welcome. Of course Comet ISON is the year’s BIGGEST celebrity. Circumstances are much better for it than PANSTARRS. ISON will pass very close to the sun in late November, be cooked into a brilliant object and develop a long tail.

Comet ISON is “rounding the corner” in Gemini the Twins this month and still very faint. It’s currently lies beyond the outer edge of the asteroid belt some 400 million miles from Earth. The Swift observation is described below. Credit: NASA

An ideal comet encounter is one where the object first passes very close to the sun then zooms by Earth soon after. This two-birds-with-one-stone trajectory allows us to see the comet near peak brightness and in its full finery. That’s exactly what will happen with ISON.

Views of Comet PANSTARRS were somewhat compromised because it receded from Earth after closest approach to the sun. It also didn’t help that the comet was more than twice as far away (101 million miles / 163 million km) when nearest Earth compared to ISON’s 40 million miles (64 million km) on Dec. 26.

On Nov. 28 Comet ISON will pass only 680,000 above the sun’s surface. Less than month later, it flys by Earth at a distance of 40 million miles. Credit: NASA

All this assumes that ISON won’t bust to bits in the intense heat it will experience during its face-to-face with the sun on Nov. 28. Back on Jan. 30, NASA’s Swift spacecraft aimed its powerful, multi-wavelength eyes at the comet when it was still near Jupiter. Even at that distance, solar heating vaporized enough ice for ISON to spew out 112,000 lbs. (51 kg) of dust a minute.

This is a tiny bit of comet dust captured by a high-flying airplane mission. The particles from ISON are similar in size – about 1/8000 of a inch across. Credit: NASA

Meteor researcher Paul Wiegert of the University of Western Ontario, who’s been using a computer to model the trajectory of dust ejected by Comet ISON, predicts that some of that dust could end up on Earth.

Less than three weeks after closest approach to our planet, Earth will pass through a flurry of the powdery stuff lofted our way by the gentle pressure of sunlight. At the same time, we’ll encounter the dust stream trailing behind ISON and headed toward the sun. Wiegert calls the double-whammy “unprecedented”.

If his forecast is correct, the dust, traveling at 125,000 mph (201,000 km/hr), will pepper Earth’s atmosphere for several days around Jan. 12, 2014. While you might expect to see a meteor shower, chances are slim; the particles are so small, they’ll slow to stop instead of getting fried as meteors by air friction. Still, you never know – maybe a few of the bigger ones will show as meteors.

Noctilucent clouds photographed from the International Space Station. Credit: NASA

As the grit drifts gently down over the months and years, it’s possible it may serve as seeds or “nuclei” for the formation of noctilucent clouds, those eerie, skeletal blue clouds visible from northern locations during the summer months. For clouds to form, water vapor needs some form of dust or grit to latch onto and grow into crystals and droplets.


For a nice visual summary of the Comet ISON dust prediction, check out this video.

Noctilucent clouds, shining in late twilight when all other clouds have gone dark, are nearly as high as the lower limit of the aurora borealis (60 miles / 96 km). While it’s only speculative, it’s possible that bits of Comet ISON may someday contribute to their formation. Wouldn’t that be just too cool?

Pretty, pretty PANSTARRS and much, much more

Look at that pretty tail! Comet C/2011 L4 PANSTARRS photographed in twilight Feb. 28, 2013 from near Perth, Australia. Details: Canon 7D, ISO 1600, 400mm lens at f/5.6. Click to see more comet photos. Credit: Roger Groom

Comet L4 PANSTARRS looks better and better with each passing night as these two photos attest. The latest birghtness estimate made a day ago puts the comet at magnitude 2.6 or only a little fainter than the stars of the Big Dipper. Yuri Beletsky, who shot the image below from the Atacama Desert in Chile, reports it was easily visible to the naked eye low above the western horizon at dusk. In a week, PANSTARRS will creep over the western horizon for northern hemisphere sky watchers and we’ll finally get to see it ourselves. Expect the comet to become visible around March 7-8 in the west about a half hour after sunset.

Two comets in the evening sky over the Atacama Desert. Comets F6 Lemmon and PANSTARRS both show lovely tails with PANSTARRS currently the brighter of the two. Click to enlarge. Credit: Yuri Beletsky

How bright will the comet glow? It’s hoped between magnitude 1 and 2 or about as bright as Deneb in the Northern Cross. If haven’t got a pair of binoculars yet, now’s the time to get down to the store and pick them up. Anything in a 8×40, 7×50 or 10×50 size will do the job. I know I’ve said it before but avoid 20x (20-power) binoculars in small sizes. The narrow field of view and high magnification will make PANSTARRS difficult to find but also and tough to hold steadily. Super high quality glass is not essential. Moderation in binoculars will bring great celestial joy.

I’ll have more detailed maps and of course tons of photos once the PANSTARRS limited-engagement, once-in-a-lifetime show begins in earnest.

The moon and Spica (to upper left of moon) this morning seen over a rooftop in Trieste, Italy. Credit: Giorgio Rizzarelli

Comets aren’t the only thing happening lately. Late last night some of you may have been lucky enough to see Spica and the moon paired up. Clouds dogged my attempts. Giorgio composed a beautiful picture of them together over a rooftop in Trieste earlier this morning.

Aurora activity ramped up last night for arctic sky watchers when a high-speed stream of solar wind rammed Earth’s magnetic field. For a brief time, minor auroras may have been visible across the far northern U.S. Activity is expected to continue tonight and then decline on March 2-3. You can always check the space weather forecast for the latest update.

NASA’s Van Allen probes (left) discovered a short-lived third Van Allen radiation belt last August only days after their launch. Credit: NASA

In a related story, NASA’s Van Allen probes discovered a third belt of radiation around Earth. We’ve known about the two Van Allen belts since 1958. They’re home to high-energy protons and electrons captured from the sun and cosmic rays from beyond the solar system and bottled up by Earth’s magnetic field. The inner belt is some 4,000 miles up; the outer belt extends from 13,000 to 37,000 miles high. Both belts swell and shrink in response to solar wind blasts and fluctuating amounts of cosmic rays.

The probes discovered a never-before-seen third belt just days after launch. Within a month it had disappeared. Exactly how, scientists are still trying to figure. If you’d like to read more about the discovery, click HERE.

Comets Panstarrs and Lemmon share a Kodak moment

Two for the price of one! Comet L4 PANSTARRS is bright dot lower left with a short tail; Comet F6 Lemmon and its skinny tail are visible at right next to the Small Magellanic Cloud, a satellite galaxy of the Milky Way. Click to enlarge. Photo taken on Feb. 17, 2013 from Australia. Credit: Justin Tilbrook

Justin Tilbrook of Australia took a marvelous image earlier this week showing our two current comet celebs F6 Lemmon and L4 PANSTARRS together in the same picture.It’s not often you’ll see two tail-toting comets captured with a wide-angle lens at the same time.

To bring you up to date, Panstarrs is still visible very low above the horizon in morning twilight from far southern latitudes. This week it’s brightened to 4th magnitude and appears like a fuzzy pearl with a short tail. One observer noted a yellow color to the comet’s head caused by dust reflecting the ever-intensifying sunlight as PANSTARRS barrels sunward toward its March 10 perihelion.

Comet Lemmon photographed on Feb. 20, 2013 through a 19.6 inch telescope. Click to enlarge Credit: Martin Mobberley

Lemmon is higher up in the sky but fainter at magnitude 5.5. Right now it might be difficult to see with the naked eye because of moonlight. Binoculars show a bright head and a  1/2-degree-long tail.

You might be interested in a recent study on brightness predictions for comets L4 PANSTARRS and ISON by Ignacio Ferrin of the University of Antioquia in Medellin, Colombia. Here are the main points:

* C/2011 L4 Panstarrs will be less bright than Halley’s Comet was in 1986. It will show
a tail easily detectable with the naked eye.

* There’s a 75% chance that  C/2012 S1 ISON will continue to brighten and put on a great show late this fall. Ferrin predicts it could become as bright as the full moon (magnitude -12.6) when nearest the sun. But his prediction comes with a caution: ISON will pass within the Roche Limit when it swings around the sun in late November. This is the minimum distance a smaller body can hold together in one piece while orbiting a larger body without being torn to bits by the larger body’s overwhelming gravity.

At top, an object like a comet has crossed the Roche Limit and starts to disintegrate into pieces. Below, the individual pieces spread out according to distance. Particles closer to the sun (left) move more quickly (red arrows) than those farther away. Credit: Wikipedia

Ferrin writes: “Any object within this limit  has a large probability of disintegrating due to differential gravitational forces from the Sun. The combinations of Roche’s Limit, plus solar radiation plus very high temperature, suggest that the comet may not survive its encounter with the Sun, disintegrating into several pieces. Or it may survive, if its internal cohesion is
sufficient to endure those conditions.”

If you’d like to learn more, please check out the complete study.

Mid-February bright comet update: Panstarrs, Lemmon, Bressi, Ison

Comet Panstarrs on Feb. 8, 2013 photographed with a 300mm telephoto lens from Castlemaine, Victoria, Australia. Observers describe very bright head and broad tail. Click to see more comet photos. Credit: Michael Mattiazzo.

There are a lot of icy mudballs , ie. comets, flying around up there at the moment, so let’s take a look at what’s happening. We’ll start with C/2011 L4 PANSTARRS, better known as Comet Panstarrs. It’s been slowly brightening to within naked eye range, hovering now right on the edge of visibility under dark skies. Recent observations by amateur comet observers put the comet a smidge above the naked eye limit at magnitude 5.5-5.7. It’s a snap to see in binoculars in morning twilight in the southern hemisphere. As you can tell from the photo, it has an intensely bright, almost star-like head and wide, dusty tail that’s about 1/2 degree long. It should be a most excellent sight in binoculars for both northern and southern hemisphere sky watchers when it emerges at dusk in the western sky next month. We’re only four weeks away!

What a comet! This is Comet Lemmon shot through a 5-inch widefield telescope on Feb. 8, 2013 from Possum Observatory Complex in Gisborne, New Zealand. Click for large version. Credit: John Drummond

Meanwhile, another comet has temporarily stolen the show. C/2012 F6 Lemmon has swelled into a huge, green leek of a thing, Like Panstarrs, it too is faintly visible with the naked eye (mag. 5.8) under dark skies for southern hemisphere skywatchers. How come they get all the fun?

A long, thin exclamation point of a tail shoots from Lemmon’s giant, whipped-up coma or cometary atmosphere. Good news is, the comet is still brightening and may reach 3rd magnitude, making it an easy sight even from the suburbs.

We northerners will have to be patient if we want a glimpse of this comet. Not until early May, when it swings around the sun and enters the morning sky at about magnitude 5, will we get our chance.

You can see the fading of Comet Bressi in this sequence of photos made by Rob Kaufman of Bright, Victoria, Australia.

Then there’s C/2012 T5 Bressi, a modest, unassuming comet that experienced a bright outburst in late January. In a matter of days it became 10 times brighter than expected. On Feb. 4, Bressi glowed at 9.2 magnitude and then slid to 10.5 the very next day.

Sad to say, this is a bad omen for a comet and usually means the beginning of the end. They are crumbly things after all and subject to breakup as their ices volatilize under the relentless sun. Unfortunately, the nail might get hammered into Bressi’s coffin on Feb. 24, when it reaches perihelion or closest distance from the sun (28 million miles). Some comet observers predict it will disintegrate around that time.

Reversed (negaitve) image of Comet ISON on Feb. 3. At the time, the comet was 4 times Earth’s distance from the sun. Credit: Rolando Ligustri / CARA Project

Finally we come to this year’s best hope for a brilliant comet – C/2012 S1 ISON. It’s still slowly cruising through northern Gemini and beautifully placed for telescopic observation every clear night for observers in the northern hemisphere. Would that it were a tad brighter. You still need a 12-inch or larger telescope to see this 15th magnitude fuzzy blotch. I shouldn’t be so offhanded. Ison has developed a short tail of late, lending it enough character to whet our appetite for things to come.

By late fall, ISON should be an easy binocular object in the morning sky. Come Christmas it’s likely to be a glorious sight at dusk. Tag along with me and I’ll let you know how it goes as the clocks ticks cometward.