Brief aurora Weds. Aug. 20-21 – maybe more overnight?

A low arc and dim green rays were topped by a red border in this photo taken around 11 p.m. CDT Wednesday night Aug. 20. Details: ISO 3200, f/2.8, 20mm lens. Credit: Bob King

Scandinavians were the lucky ones yesterday when auroras broke out during their nighttime. Here in the U.S. it was still afternoon. Auroras are mighty scarce in sunshine.

Tonight to my surprise, we had a brief display around 11 p.m. CDT.  An arc rose above Boulder Lake north of Duluth, Minn., where a group of naturalists and I spent the night at the telescope under a starry sky. At the sight of a few needle-thin rays, one in our group jumped in a canoe and paddled out into the lake for a better view.

More rays taken a few minutes after the first photo. The display was fairly quiet and reached to about 10 degrees above the northern horizon. Credit: Bob King

Not 15 minutes after it began, the arc and rays faded away, leaving only a faint, diffuse glow until fog settled in around midnight. The Kp index rose slightly during the evening, and the ACE satellite plot has shown a southward pointing Bz or solar magnetic field in Earth’s vicinity for many hours. This is often a good indicator of auroral activity on the way.

The show was subtle but no one was disappointed. Auroras are always welcome around here.

Aurora alert tonight Aug. 19-20 for northern U.S.

“Unbelievable,” says Reid Wiseman on seeing a spectacular auroral display from a window on the International Space Station this evening. This photo was tweeted out at 6 p.m. CDT. Credit: NASA/Reid Wiseman

The astronauts are seeing it from the space station. You and I just might too. A G2 moderate auroral storm kicked up this afternoon and early evening, and according to NOAA space weather experts, is expected to continue into the night.

Another shot of the aurora from orbit. “Never in my wildest dreams did I imagine this,” said Wiseman.

A coronal mass ejection (CME) caused by a filament or plume of hydrogen gas ejected a few days ago caused the sudden surge. The Kp index, a reliable indicator of magnetic activity in Earth’s upper atmosphere hit 6 earlier this evening. Should it ‘stick’ there, skywatchers in Canada and across the northern U.S. stand a good chance of seeing auroras tonight. Look to the north at the onset of night. I’ll keep you posted.

* Update 11 p.m. CDT: The Kp has plummeted to 2! That’s not good. It’s always possible that activity will shoot up again overnight. If you’re out tonight, take a look before going to bed.

Aurora alert tonight Aug. 2 / Rosetta comet update – striking new details!

A CME or coronal mass ejection erupting on July 30 may lead to a small display of northern lights tonight. Jupiter at right in this photo made with the coronagraph on the Solar and Heliospheric Observatory. Credit: NASA/ESA

Minor auroras might visit skies across the northern U.S. and southern Canada tonight, the result of a coronal mass ejection from an erupting filament on July 30. Filaments are clouds of hot hydrogen gas suspended in the sun’s lower atmosphere. They often stay put for days, but a little magnetic instability can launch one into space.

Material from the filament is expected to begin arriving this afternoon and continue into the evening hours. I’ll have an update later if auroras materialize. Meanwhile, keep an eye on the northern horizon when it gets dark tonight. Fortunately, the moon will only be a half and not wash out the sky.

Comet 67P/Churyumov-Gerasimenko at 621 miles (1,000 km) on August 1. Wow! Look at that richly-textured surface. This photo has higher resolution than previous images because it was taken with Rosetta’s narrow angle camera. The black spot is an artifact. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta sent two new pictures of Comet 67P/C-G from 621 miles (1,000 km) away that show striking new details including new artifacts. I’ve done some digging around and discovered that the dome-like features and ‘craters’ seen on the past couple photos are really artifacts due to image processing.

Wider-angle and lower resolution navigation camera photo of the comet. More artifacts are seen including what look like bumps or boulders. Credit: ESA

You’ll see a black spot (artifact) in the narrow-angle camera and another dome artifact in the Navcam photo. They’re generally pairs of bad pixels that get smoothed out in processing to look like real features on the comet’s surface. Those should go away once the spacecraft is close enough for the comet to fill the field of view.

Huge sunspots scar the sun this week

Ten groups including three visible with the naked eye protected with a safe filter dot the sun today. Photo by the Solar Dynamics Observatory (SDO) taken at 8 a.m. CDT today July 9. Credit: NASA

A trio of impressive sunspot groups are parading across the sun’s face this week. Regions 2108, 2109 and 2110 are all closely-spaced and near the center of the disk today. All three require nothing more than a pair of eyes and a safe solar filter to view.

The sun seen through a standard 200mm telephoto lens and solar filter this morning gives you an idea of how the big sunspot groups look to the naked eye. Credit: Bob King

I took a look through my handy #14 welders glass this morning and saw 2110 distinctly; the other two groups blended into a single ‘spot’ at first. Looking closely I could barely split them into two separate dots. The view was spectacular at 30x in my little telescope with a total of ten sunspot groups and lots of fine detail in the three biggest.

Given high sunspot counts, the chance for flaring has been increasing in recent days. Today there’s a 75% chance for moderately strong M-class flares and 20% chance for the most powerful X-class variety.

Safe solar filters come in several varieties of optical / coated plastic and glass. Click to see ones you can purchase from Rainbow Symphony. Credit: Bob King

Curiously, none of the three biggies has shot off a large flare in the past day or two; they’re all currently stable. But the inconspicuous group 2113 fired off a beefy M6 flare only yesterday. It’s not expected to affect Earth, but because 2113 hides a complex magnetic field, future M-class or stronger blasts may be possible.

M6-class solar flare eruption from sunspot group 2113 captured July 8, 2014 at 11:24 a.m. by SDO. Credit: NASA

It seems like we’re due for aurora, so I’d be surprised if the current activity doesn’t lead to at least a minor storm soon. I’ll keep you updated.

Chance for auroras tonight June 21-22 / Comet Jacques approaches the sun

A large cloud of hydrogen gas called a filament erupts from the sun on June 19, 2014. We normally see these fiery gas clouds along the sun’s limb as pink flames. Here it shows in silhouette.

Welcome to the first day of summer! The new season’s first night may just bring us a blush of northern lights. A filament – another name a solar prominence except seen in silhouette against the sun’s bright disk – erupted from the sun’s southern hemisphere Thursday. Flung into space because of some magnetic disturbance, most of the material shot off to the northeast, but some was Earth-directed. It should arrive overnight and possibly set off a minor aurora storm.

A portion of a CME / filament eruption Thursday may spark auroras tonight and tomorrow night. This photo was  made with the coronagraph on the Solar and Heliospheric Observatory. Credit: NASA/ESA

NOAA forecasters are calling for a 25% chance of a minor storm for mid-northern latitudes tonight and a 20% chance Sunday night.

The picture above showing the coronal mass ejection was taken with the Solar and Heliospheric Observatory’s coronagraph, a special camera with an occulting disk that blocks direct sunlight so astronomers can see what’s going on around the sun. Photos taken today with the instrument show a new visitor – Comet Jacques. You can watch it enter the field of view at lower left.

There are faint hints of a tail in these 24 consecutive images compiled into an animation by Rob Kaufman.

Amateur astronomer Rob Kaufman compiled multiple still photos into a video showing the ‘blip’ on the move. It’s currently around magnitude 7, but once it passes the sun and moves into the morning sky next month, it may be bright enough to spot in binoculars. More on that as the time approaches.

Another erupting filament photographed late Friday night June 20 with NASA’s Solar Dynamics telescope.

Surprise aurora puts on Sunday morning show

Sallie Carlson of Lutsen, Minn. took this photo this morning June 8, 2014. She reported aurora visible overhead and rays bright enough to overtake the light of the gibbous moon. Copyright: Sallie Carlson

Ouch! Missed a great aurora this morning. The potential was there late yesterday afternoon when the magnetic field bundled with the solar wind tilted south and hooked into Earth’s magnetic domain. Activity increased but nothing was visible here in Duluth up till midnight. Moonlight may have washed out any early, low aurora present.

That all changed sometime around 1 a.m. right about the time I entered dreamland. Others who stayed up late reported lots of red rays visible even from moderately light-polluted locations:

“1:45 am. slight calm after 45 mins of intense displays with lots of red showing even in my semi-urban location,” said reader Paul Contant of Penticton, British Columbia, Canada.

Bar chart showing the jump in the Kp index overnight. A southward tip in the interplanetary magnetic field (which originates on the sun) and increase in the speed of the solar wind were responsible for the display. Activity is ramping down this morning but there’s still a chance for auroras tonight. Credit: NOAA

Auroras were seen all the way to the zenith throughout the morning hours as the Kp index, an indicator of magnetic activity high overhead, surged to ’6′ spawning a G2 moderate magnetic storm.

An all-sky aurora with green and purple curtains early starting up about 1:30 CDT and going until dawn as seen from southern Alberta, Canada. The Big Dipper is above the Barn. The purple color is from blue scattered sunlight hitting the red tops of the auroral curtains. Details: 16-35mm lens at f/3.2, 20 seconds at ISO 1600. Copyright: Alan Dyer

This morning’s aurora was a complete surprise. Mostly quiet conditions were expected and still are. NOAA’s space weather center calls for only a small chance for auroras tonight but you better believe I’ll be on the lookout. Let us know if you see anything, too.

Magnetic collapse makes Saturn’s auroras dance the cha-cha

Images of auroras over Saturn’s north pole in ultraviolet light with the Hubble Space Telescope capture moments when Saturn’s magnetic field is affected by bursts of particles streaming from the Sun. Click to enlarge. Credit: NASA, ESA, Jonathan Nichols (University of Leicester)

Saturn shines brightly in the late May evening sky. You can see it now at nightfall by following an arc starting with fiery Mars and passing through Spica. Continue and you’ll end up at Antares, the alpha luminary in Scorpius. Did you know that it also shimmers with auroras too just like the Earth?

Recent Hubble Space Telescope photos taken in ultraviolet light, where the aurora shines brightly, show bursts of light shooting around Saturn’s polar regions traveling at more than three times faster than the speed of the gas giant’s roughly 10-hour rotation period.

Saturn’s auroras shine brightly in UV but would appear deep red at the bottom and violet at top with the naked eye. That’s because hydrogen gas dominates the planet’s atmosphere and emits light in different colors when bombarded by the energetic electrons in the solar wind. On Earth, excited oxygen and nitrogen molecules produce the more familiar greens, reds and blues of northern lights.

A magnetosphere is that area of space around a planet that’s controlled by the planet’s magnetic field. The shape of the Earth’s magnetosphere is the direct result of being blasted by solar wind, compressed on its sunward side and elongated on the night side forming a magnetotail. Saturn’s is similar. Credit: NASA

University of Leicester researchers recently discovered an amazing connection between Saturn’s and Earth’s auroras. Both planets are surrounded by teardrop-shaped magnetic domains called magnetospheres generated by the churning of materials within their cores. In each case, the side facing the sun is compressed and flattened, while the other side is drawn out into a long tail called a magnetotail.

“Our observations show a burst of auroras that are moving very, very quickly across the polar region of the planet. We can see that the magnetotail is undergoing huge turmoil and reconfiguration, caused by buffering from solar wind,” said Jonathan Nichols, of the University of Leicester’s Department of Physics and Astronomy, who led the Hubble observations.

NASA’s THEMIS Spacecraft See magnetic reconnection / collapse in Earth’s magnetotail

What’s happening – and you can see it clearly in the video above – is that the incoming solar wind connects to and ‘peels back’ a portion of the magnetic field on the dayside of both Earth and Saturn. When the lines pinch together and reconnect on the back or magnetotail-side, a torrent of solar electrons is funneled into the upper atmospheres of both planets. Voila – aurora borealis! Here’s another video showing it from a slightly different perspective.

Dance of Saturn’s auroras

“The particular pattern of auroras that we saw relates to the collapsing of the magnetotail,” Nichols added. “We have always suspected this was what also happens on Saturn. This evidence really strengthens the argument.”

Cool beyond cool. Earth and Saturn are auroral buddies.

Follow the arc from fiery Mars in the south through Spica to find Saturn. Keep going all the way to Antares. All four are magnitude 1 or brighter. The map shows the sky around 10:30 p.m. local time facing south. Stellarium

Surprising aurora puts on great show last night

Auroral arcs are topped by red rays light up the northeast while the moon (0verexposed) and Jupiter shine off to the west in this photo taken last night over a small lake north of Duluth, Minn. Both moon and aurora light are reflected in puddles on the ice. Credit: Bob King

No, it wasn’t in the forecast but just the like real weather, the unexpected happens. A change in the “magnetic direction” of the wind of particles from the sun called the solar wind from north to south made all the difference. Earth’s magnetic field points northward. When the field associated with a batch of plasma from the sun points southward, as it did beginning early yesterday evening, there’s a good chance it will link into our field and ultimately allow those particles passage into our upper atmosphere.

A large red patch briefly glowed above the bright green arc around 11:15 p.m. last night May 3. The color was dimly visible with the naked eye. Credit: Bob King

Spiraling down magnetic field lines like firefighters on a firepoles, billions of tiny solar electrons strike oxygen and nitrogen molecules in the thin air 60-125 miles up. When the excited atoms return back to their normal rest states, they shoot off niblets of green and red light that wash the sky in multicolor arcs and rays.

The whole northern sky lit up with green and red rays earlier this morning. While the green color was easy to see, the red was very pale. The human eye is much more sensitive to green light than red, one of the reasons why the aurora rarely appears red except in a camera during a time exposure. Credit: Bob King

Nothing in the space weather forecast would have led you to believe northern lights were in the offing for mid-latitude skywatchers last night. Maybe a small possibility of a glow very low on the northern horizon. Maybe. Instead we got the full-blown show with auroras of many forms jumping, glowing and dancing all night long. When I finally hit the hay at 4 a.m. flames of moderately bright aurora still rippled across the north.

So what about tonight? Just like last night, there’s only a 5% chance of a minor storm. Like I always say, take a look anyway, because nature always has a surprise or two up her sleeve.

Aurora out tonight May 3-4 over northern U.S.

There may be a lot of trees in this view but they don’t hide the fact that the northern lights are visible tonight right now (10:30 p.m. May 3) low in the northern sky. Take a look if it’s clear by you. Credit: Bob King

(UPDATE May 4: Click HERE to see what a fine show the aurora gave us overnight.)

Watch for auroras tonight. 15 minutes ago, a bright arc lit up in the northern sky here in Duluth, Minn. No way to know if it will fade or go wild, so be sure to take a look if it’s clear tonight. The magnetic field in the solar wind tipped southward this evening, weaseling a connection to Earth’s own magnetic domain and sparking a small display of northern lights. I’m headed back out for more. Good luck – let’s hope it continues.

Aurora watch for northern U.S. overnight April 29-30

Map compiled with satellite data showing the extent of the auroral oval at midnight (CDT) tonight. Credit: NOAA

A stream of high-speed particles from a coronal hole on the sun is blowing by Earth tonight and causing an uptick in auroral activity across Canada. Some of that appears to be spilling into the northern U.S. at this hour, so keep an eye out for a green glow or low arcs spanning the north if your sky is clear. We’re cloudy here in Duluth, Minn. so no first-hand report.

Just for a taste, here’s a beautiful aurora photographed from Faskrudsfjordur in eastern Iceland on April 19, 2014. Credit and copyright: Jónína Guðrún Óskarsdóttir