Farewell Orion / See a Dragon / Aurora update

Orion's Belt (left) is reflected in calm waters in  a lake north of Duluth as the constellation tilts toward the western horizon last night. Credit: Bob King

Orion the Hunter and his three belt stars (left) are reflected in a lake north of Duluth last night. Venus, along with the Hyades and Pleiades star clusters, shine at right. Credit: Bob King

Last night while watching the northern lights, we saw the Great Hunter head for the hills. Orion has been the center of attention since December, as recognizable in the southern sky as the Big Dipper is in the north. Now he’s trotting off toward the western horizon, replaced by Jupiter, Leo and the constellations of spring.

Like a furniture clearance commercial that airs during the nightly news, ALL WINTER CONSTELLATIONS MUST GO! With new inventory coming in, the sky’s gotta make room.

Like it or not, Orion will toddle out of the picture soon. The rising and setting of the stars is a reflection of our planet’s rotation; the Earth spins toward the east, pushing up new stars from the eastern horizon and leaving those in the west behind. We see this grand parade every clear night.

View of Earth's orbit around the sun seen from above the northern hemisphere. As our planet moves to the left, the background constellations appear to drift to the right or westward. Credit: Bob King

View of Earth’s orbit around the sun seen from above the northern hemisphere. As our planet moves to the left during its yearly swing around the Sun, the background constellations appear to drift to the right or westward. Credit: Bob King

But there’s a more subtle shift happening at the same time. As Earth travels in its orbit around the sun, we peer out into different sectors of the sky at night as the weeks and months pass. Like a runner facing a different set of fan-packed bleachers while circling the track in a 1000-meter race, Earth faces Orion in winter, Leo in spring, Scorpius in summer and Pegasus in the fall.

They constellations appear to drift westward very gradually at the rate of about 1° per day. That’s small enough we don’t notice night to night. But the degrees add up. In two weeks, a constellation will drift about 14° to the west — more than the length of your fist held at arm’s length against the sky.

To see this for yourself, find a bright star like Betelgeuse in Orion or Arcturus in Bootes (located below the Big Dipper’s Handle) and note its position in relation to a nearby landmark like a church steeple, mountaintop or Pizza Hut at a particular time. Wait a few nights and then return to the exact same spot at the same time, and you’ll see that the star has slid westward.

Just the way the rising and setting of the stars is an illusion caused by Earth’s rotation, the seasonal drift of the stars and constellation is a sleight of hand caused by Earth’s revolution around the Sun. Now you know why the stars can sit still — it’s YOU who’s doing the moving.

Earth zips around the Sun at a speed of 18.5 miles per second (30 km/sec), covering 26,640 miles each day. In the time it takes for you to notice your reference star has moved – we’ll say 3 nights – you and the home planet have traveled nearly 80,000 miles!

Falcon 9 was carrying the Dragon spacecraft, which is loaded with about 4,300 pounds of supplies and payloads bound for the International Space Station (ISS). Credit: SpaceX

Falcon 9 lifts off April 14 carrying the 9,300-pound Dragon spacecraft, which was loaded with about 4,300 pounds of supplies and payloads for the International Space Station (ISS). Credit: SpaceX

Being outside at night can be a wonderful thing because you inevitably see something unexpected. Two nights ago, I was out with my astro class and we saw the weirdest pair of satellites in the northeastern sky – a bright one and a faint companion just a few degrees apart. Both moved quickly and faded out in less than a minute.

I later discovered we saw the Dragon cargo ship en route to deliver supplies to the International Space Station and the upper stage of the Falcon 9 rocket that lofted the ship into orbit.

You can see either or both in the next few nights by going to Heavens Above and selecting your city and then clicking on the Dragon CRS-6 link just below the ISS link under the Satellites heading. Passes are only a minute or two long and occur in evening twilight. The brighter object will be the rocket stage.

The Falcon rocket's second stage engine burns for about 7 minutes to deliver the Dragon ship to its initial orbit. Credit: SpaceX

The Falcon rocket’s second stage engine burns for about 7 minutes to deliver the Dragon ship to its initial orbit. Credit: SpaceX

Bring binoculars and you might still be able to see the solar panel covers that were ejected from the Dragon as separate fainter objects nearby. Dragon will arrive at the space station around 6 a.m. CDT tomorrow (April 17), when astronauts will use the robotic arm to secure it. I expect that tonight, Dragon will follow the ISS by only a couple minutes.

Last night’s aurora glowed until the wee hours. I hope you were able to see at least some of the show. Tonight, forecasters predict another chance for more northern lights though they’re expected to be a little “quieter” than yesterday.

Nature cooks up a fine aurora tonight – don’t miss it

A tall red beam of aurora stands up from the lower green rayed arc in the northern sky around 10:30 p.m. tonight. Even to the eye, this one was obviously pink. Credit: Bob King

A tall red beam of aurora stands up from the lower green rayed arc in the northern sky around 10:30 p.m. tonight. Even to the eye, this clearly looked pink. Credit: Bob King

I can’t believe it. The northern lights are back … again! Sure, they were in the forecast, but that doesn’t always mean they’ll show up.

It’s been quite a wonderful pageant tonight. Lots of rayed arcs with occasional Star Wars “lightsaber” beams. The delicate pink coloration in the ray pictured above was one of the most beautiful I’ve seen in several years of aurora watching.

Around 10:15 p.m. tall, faint red rays stretched toward the North Star from an active green arc. Venus is reflected in the lake at left. Credit: Bob King

Around 10:15 p.m. tall, faint red rays stretched toward the North Star from an active green arc. Venus is reflected in the lake at left. Credit: Bob King

There was a lot of action, but nothing too fast. Rays and rayed arcs slowly materialized, hung back and then reformed over and over in a way that reminded me of a symphonic theme and variations.

Multiple rayed arcs are reflected in still waters in a lake north of Duluth, Minn. Wednesday night. Credit: Bob King

Multiple rayed arcs are reflected in still waters in a lake north of Duluth, Minn. Wednesday night. Credit: Bob King

The Kp-index sits at “5” or minor storm, and the northern lights are still out there as I write. If you can find a dark sky with a good view to the north, I encourage you to lose a little sleep to see what natures’s offering tonight.

* Update 1 a.m. Thursday April 16 – The aurora is now in the flaming phase, where pulses or waves ripple through the lights from bottom to top across the entire northern sky. Although the rays are now fainter, they reach all the way to the zenith compared to earlier in the evening. What are you seeing? Let us know by clicking on and adding a comment.

Red and green all over! Credit: Bob King

Red and green all over! Credit: Bob King

Aurora alert tonight April 15-16

What a display! The aurora on the morning of April 11, 2015 reflected in St. Croix River near Gordon, Wis. Credit: Kathleen Wolleat

What a display! The aurora on the morning of April 11, 2015 reflected in the St. Croix River near Gordon, Wis. Credit: Kathleen Wolleat

Good news on the northern lights front. Earth’s expected to get a bath from subatomic particles streaming from the Sun’s southern hemisphere tonight. They originate from a gap in its magnetic canopy called a coronal hole.

A big, extended coronal hole in the Sun's atmosphere or corona is sending a high-speed package of solar wind our way tonight. This photo was taken on April 13 by NASA's Solar Dynamics Observatory. Credit: NASA

A big, extended coronal hole in the Sun’s atmosphere or corona is sending a high-speed package of solar wind our way tonight. This photo was taken on April 13 by NASA’s Solar Dynamics Observatory. Credit: NASA

Not a big storm. The space weather office at NOAA is calling for a G1 or minor geomagnetic storm, the type that brings arcs and occasional rays of aurora across the northern U.S. and southern Canada.

The last G1 storm we experienced on April 11 produced a fat, quiet arc that broke up into a modest but attractive display visible as far south as Colorado.

The best time to watch for tonight’s possible show will be from nightfall – around 8:30 p.m. – until midnight. In other words, on the early end. There’s no moon in the sky and April brings some of the most pleasant, mosquito-free evenings of the year.

Aurora over Boulder Lake north of Duluth, Minn. on April 11, 2015. Credit: Deb Carroll

Aurora over Boulder Lake north of Duluth, Minn. on April 11, 2015. Credit: Deb Carroll

The northern lights often begin as an arc or rainbow-shaped glow low in the northern sky. When night has begun, the light lingers in the north as if twilight isn’t over yet. Don’t be fooled. That’s the aurora gearing up.

Pleiades passage / Aurora night 3?

Venus nearly overwhelms the Seven Sisters or Pleiades star cluster yesterday evening around 9 p.m. in the western sky. Watch for the two to be nearly as close together tonight. Credit: Bob King

Venus nearly overwhelms the Seven Sisters or Pleiades star cluster yesterday evening around 9 p.m. in the western sky. Watch for the two to be nearly as close together tonight. Credit: Bob King

You couldn’t help noticing Venus and the Pleiades last night glimmering in the west at dusk. Tonight they’ll be nearly as close. If you have a small telescope, take a closer look and see if you can discern the planet’s small, not-quite-round disk.

Venus passes through phases just like the moon and has surprised more than a few first time viewers who thought that’s what they were looking at. A moon in miniature but shiny white and without a bump or crater to mare its smooth and perfect “skin”. Unlike the moon, Venus is 100% cloaked in clouds. From its surface you wouldn’t see a single star not just for a week or two but for as long as you’d live. If there were ever a nightmare planet for amateur astronomy, this is it.

As Venus revolves around the Sun interior to Earth's orbit, we see it go through phases depending on its position in relation to the Sun.  Credit: Wikipedia

As Venus revolves around the Sun interior to Earth’s orbit, we see it go through phases depending on its position in relation to the Sun. Credit: Wikipedia

Venus orbits the Sun inside of Earth’s orbit — the reason we see lunar-like phases — with a period of 225 days. That makes a Venusian year only 0.6 times as long as an Earth year. For those who love birthdays then, Venus offers nearly twice as many as our plodding planet.

Through April, Venus appears as small waxing gibbous moon through a telescope, but as it catches up to Earth, it will gradually slim down to a half-moon and finally a crescent. Because it’s approaching our planet, its apparent size will also increase. By crescent phase, Venus’ shape is easily visible in little more than 10x binoculars.

While Venus is 106 million miles (170 million km) from us today, that’s peanuts compared to its neighbor, the Pleiades, which beckons from a distance of 444 light years or 2.66 quadrillion miles.

The aurora at 3:27 a.m. this morning April 10 from Midway Township near Duluth, Minn. Moonlight lit the foreground. Credit: Matthew Moses

The aurora at 3:27 a.m. this morning April 11 from Midway Township near Duluth, Minn. Moonlight lit the foreground. Credit: Matthew Moses

I can vouch that the northern lights remained active all the way into twilight this morning. Even with the last quarter moon shining, a rayless hump of aurora glowed brightly in the lower half of the northern sky until finally quenched by dawn. Chances for seeing northern lights drop off this evening, but there may still be some action. Once again, watch for a glow in the north as soon as the sky gets dark.

Last night, a low auroral arc minded its own business for a very long time before surging into activity. I stood out on a dirt road somewhere north and watched the slow, slow process unfold to the sound of a single saw-whet owl’s relentless peeping.

More auroras forecast / Venus snuggles up to the Pleiades

Time lapse of the aurora from Spirit Lake, Idaho April 9-10 by Donny Mott. Things get interesting about halfway through.

Yes – auroras made a sweep of the sky overnight and were visible as far south as Colorado. Unfortunately they weren’t particularly bright in part because of moonlight. But through the camera lens, the rays and arcs shone as a kaleidoscope of red, green and purple.

 Paul Zizka took this beautifully composed aurora portait last night from Athabasca Glacier, Jasper National Park, Alberta, Canada. "when the sky filled with aurora Im pretty sure I started screaming like a little girl. The aurora showed a wide array of colours and shapes over the Canadian Rockies and lasted several hours. Dream come true." Credit: Paul Zizka

Paul Zizka took this fantastic aurora portrait last night from Athabasca Glacier, Jasper National Park, Alberta, Canada. “When the sky filled with aurora, I’m pretty sure I started screaming like a little girl. The aurora showed a wide array of colors and shapes over the Canadian Rockies and lasted several hours. Dream come true.” Credit: Paul Zizka

It appears that activity kicked in a little later than expected – mostly after midnight – but raged till dawn. Expect a continued chance for northern lights tonight especially before midnight.

Venus passes closest to the Seven Sisters star cluster a.k.a. the Pleiades tonight and tomorrow. Created with Stellarium

Venus passes closest to the Seven Sisters star cluster a.k.a. the Pleiades tonight and tomorrow. This view shows the sky facing west around 8:45 p.m. local time in late dusk this evening. Created with Stellarium

There’s more than one cool thing happening in this evening’s sky. Look west at late dusk and fix your gaze on the brilliant planet Venus. When you do, you’ll notice some fuzzy stars only 2.5° away — the Pleiades!

The brightest planet passes closest to the sky’s most awesome star cluster this evening and next. What a contrast they make. Venus so shockingly luminous set against the delicate twinkle of the cluster stars. I encourage you to use your binoculars to appreciate them together under a little bit of magnification. It’s not often that both neatly fit in the same field of view.

You’ll also discover that the Seven Sisters, an alternate name for the Pleiades, is something of a misnomer. With 7x or 10x magnification their number increases dramatically. I dare you to count them. For more about the event and the curious 8-year-cycles of Venus-Pleiades visits, click HERE.

Dawn near Ceres – approach images, videos and animations

Today or tomorrow we should be seeing a new set of higher resolution photos of the dwarf planet Ceres taken by NASA’s Dawn spacecraft today. Check back later and hopefully we’ll have some fresh views of crescent Ceres.

Chance for northern lights tonight April 9-10

A coronal mass ejection sent our way by sunspot group 2320 (right of center) will arrive at Earth later today and possibly fire up auroras tonight. Credit: NASA/SDO

A coronal mass ejection sent our way by sunspot group 2320 (right of center) will arrive at Earth later today and possibly fire up auroras tonight. Credit: NASA/SDO

A small scale but Earth-directed particle blast from the Sun on April 6 will arrive later today and hopefully ring our planet’s magnetospheric bell overnight.

NOAA space weather experts forecast a G1 minor geomagnetic storm peaking this evening between sunset and 10 p.m. (CDT) and continuing at a lower level through the night.

G1 conditions usually mean an aurora that appears in the lower half of the northern sky from the northern tier of states and Canadian provinces. With no moon till after midnight, conditions are perfect for seeing even faint auroras. The first thing I look for is a low, pale green arc quietly biding its time 5° or three finger-widths above the northern horizon.

The Sun early this morning photographed by the Solar and Heliospheric Observatory (SOHO). The Sun itself is hidden behind a opaque disk, so we can better see its corona - the spiky stuff. The planet Mercury is only 1° from the Sun and will soon make its best appearance of the year in the evening sky late this month. Credit: NASA/ESA

The Sun photographed early this morning by the Solar and Heliospheric Observatory (SOHO). The Sun itself is hidden behind a opaque disk, so we can better see its corona – the spiky stuff. The planet Mercury is only 1° away and will make its best appearance of the year in the evening sky later this month. Credit: NASA/ESA

If activity increases, a second, higher arc often appears, and if we’re lucky, its bottom border will brighten and break up into whirling rays. Keep an eye out tonight!

St. Patrick’s Day aurora storm strongest in a decade

Using the “day-night band” (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS), the Suomi NPP satellite acquired this view (above) of the aurora borealis around 1:30 a.m. Eastern Daylight Time on March 18, 2015. Auroras appear as white streaks over Hudson Bay, southern Canada, and the northern United States. The DNB sensor detects dim light signals such as auroras, airglow, gas flares, city lights, and reflected moonlight. In the image above, the sensor detected visible light emissions as energetic particles rained down from Earth’s magnetosphere into the gases of the upper atmosphere.

The Suomi NPP satellite photographed the aurora borealis around 12:30 a.m. CDT on March 18, 2015. Auroras appear as white streaks over Hudson Bay, southern Canada, and the northern United States. In the image above, the sensor recorded the emission of light as energetic particles rained down from Earth’s magnetosphere into the gases of the upper atmosphere. Credit: NASA/Suomi NPP – VIIRS

Earth celebrated St. Patrick’s Day on March 17 with vivid red, white and green auroras seen as far south as the southern U.S. and as far north as New Zealand in the southern hemisphere.

It turns out the geomagnetic storm that sparked the lights was the strongest in a decade. On Sunday, March 15, a coronal mass ejection exploded off the Sun towards Earth as seen by the Solar Heliospheric Observatory (SOHO).

The Kp index over the three days starting March 16 tells the story of the geomagnetic storm in red bars of high activity. The times shown are CDT at the height of the storm. Credit: NOAA

The Kp index over the three days starting March 16 tells the story of the geomagnetic storm in red bars of high activity. The times shown are CDT at the height of the storm. Credit: NOAA

By March 17, the burst of solar particles and energy reached Earth and kept the solar wind stream at potent levels for more than 24 hours. The storm reached a G4 or “severe” level on NOAA’s geomagnetic storm scale. Meanwhile, the Kp index, an indicator of global geomagnetic storm activity, fluctuated between 6 to 8 on a scale that goes to 9.

The storm peaked during the daylight hours for observers in the U.S. and Canada. Some observers caught it on the rise in the early morning hours of the 17th while many more saw it rage into the night. Auroras continued to reverberate – albeit on the quieter side – for the remainder of the week.

The Aurorasaurus site was designed by researchers from the New Mexico Consortium, NASA, Pennsylvania State University, and Science Education Solutions to improve chances for people to catch an aurora by collecting real-time tweets and information from other sites. Credit: Aurorasaurus

The Aurorasaurus site was designed by researchers from the New Mexico Consortium, NASA, Pennsylvania State University, and Science Education Solutions to improve chances for people to see an aurora by collecting real-time tweets from aurora watchers. Credit: Aurorasaurus

Many people submitted photos and observations of the display through the Aurorasaurus website, a new citizen science project that aims to improve chances for folks to see an aurora by collecting and sharing tweets and information from other sources in real-time. Aurorasaurus gathered 35,000 aurora-related tweets and reports and confirmed 250 of them as positive sightings.

The project’s designers hope to improve our understanding of the auroral oval, two rings-shaped zones of auroras centered on Earth’s geomagnetic poles.

Auroras may return tonight, Saturday

Aurora near Yellowknife, Northwest Territory, Canada during the big St. Patrick's Day display. Credit: Joe Culler

Amazing curtains of aurora breaking up into rays near Yellowknife, Northwest Territory, Canada during the big St. Patrick’s Day display. Credit: Joe Culler

Thanks to a change-up in the solar wind called a co-rotating interaction region (CIR) followed by more gusty winds from a hole in the Sun’s corona, we have a shot at seeing auroras both tonight and Saturday night. CIRs are compression regions between a slow-flowing solar wind and a fast one. Material can pile up in a CIR, creating delicious auroral havoc upon its arrival at Earth.

Multiple curtains of northern lights float over conifers near Yellowknife during the mid-March aurora storm widely seen across the central and northern U.S. Credit: Joe Culler

Multiple curtains of northern lights float over conifers near Yellowknife during the mid-March aurora storm widely seen across the central and northern U.S. Credit: Joe Culler

NOAA space weather experts are calling for G1 minor geomagnetic storms during the hours leading up to midnight both nights. Minor storms usually mean auroras across the northern parts of the northern states and southern Canada, but as you’re probably aware, the magnetic direction of material coming our way makes a big difference as to whether it creates a storm.

If the south pole of the cloud brushes our magnetic domain, it’s far more likely to connect with Earth’s northward-pointing field. Like magnets snapping together, cloud and Earth-field are drawn to each other. Particles from the Sun can then follow Earth’s magnetic field lines into the polar regions where they strike and excite the atoms that produce the aurora.

ACE plot of magnetic field direction or Bz from last night. You can see how the storm dissipated once the magnetic direction of the cloud changed from south (during the storm) to north (above the white horizontal line). Credit: NASA

ACE plot of magnetic field direction or Bz from a storm last September. You can see how the storm dissipated once the magnetic direction of the cloud changed from south (during the storm) to north (above the white horizontal line). Credit: NASA

I always check the Bz, a measure of whether the arriving solar wind is pointing north or south. When the Bz drops below the centerline and especially if it’s at -10 or lower (south), there’s a fair chance you’ll see northern lights. Click over the ACE satellite page to check to get the lowdown on the Bz. Use the topmost graph with the red squiggly line.

The 8-day-old moon will fill your eyes with craters. Credit: Bob King

The 8-day-old moon will fill your eyes with craters. Credit: Bob King

Unlike the recent St. Patrick’s Day display, which happened in a moonless sky, we have an 8-day-moon to contend with tonight. That’s not an aurora killer but it will reduce contrast. Also, don’t be fooled by a lighter horizon in the northern sky. Normally, that’s a sign of aurora, but moonlight can also make the sky near the horizon appear brighter.

Not that there’s anything wrong with the moon. Now’s the best time to see it in a telescope – it’s high in the south and its current phase shows off a spectacular diversity of craters and land forms.

Let’s hope we get a nice aurora sometime this weekend.

One other tidbit for those following the nova in Sagittarius (Nova Sagittarii 2015 No.2). After fading early this week to around 6th magnitude, it’s rebrightened! I was surprised to see it back up to 5.0 this morning.

Nova in Sagittarius brightens / Aurora keeps on truckin’

Photo of the Teapot constellation Sagittarius this morning March 21 with the nova. The best time to see it is at the start of dawn when the star is highest in a dark sky. Credit: Bob King

Photo of the Teapot constellation Sagittarius this morning March 21 with the nova. The best time to see it is at the start of dawn when the star is highest in a dark sky. Credit: Bob King

The nova in Sagittarius discovered last week is on its way UP! Since then, it’s brightened to around magnitude 4.5, making it relatively easy to see with the naked eye if you know just where to look. It’s also been christened Nova Sagittarii 2015 No. 2, a temporary designation.

It surprised me this morning at +4.4 — easy to see from a dark sky alongside the spectacular southern Milky Way. It’s uncommon to see one of these stellar explosions with the naked eye. That’s why I encourage you to seize the opportunity. The last time one was this bright was back in August 2013 when Nova Delphini (V339 Del) popped off at +4.3.

This AAVSO chart will not only help you pinpoint the nova but also has stars labeled with their magnitudes or brightness. Decimals are omitted, so a star marked 47 is magnitude +4.7. Credit: AAVSO

This AAVSO chart will not only help you pinpoint the nova but also has stars labeled with their magnitudes or brightness. Decimals are omitted, so a star marked 47 is magnitude +4.7. The PNV title refers to Possible Nova. The nova’s has since been confirmed. Credit: AAVSO

You can use the photo and the AAVSO chart to take you right there. The nova’s not so bright that you can just walk outside and look up and see it. Find a location with a wide open view to the southeast, get oriented in the Teapot and then use binoculars. Once you’ve located the nova this way, try spotting it with your eyes alone.

Checking the list of recent observations submitted by observers with the American Association of Variable Star Observers (AAVSO) the nova’s been trending upward in brightness since discovery. Who knows? There’s a good chance it could brighten further.

Telescope users should keep an eye out for changes in the nova’s color. Right now it’s pale yellow as we see a mix of light from the bluish explosion on the surface of the white dwarf and the red-light-emitting expanding cloud of debris around it. Over time, many novae redden as the explosion plays out and they cool. As with Nova Delphini, color changes over time can be striking and worth the extra effort to follow.

A short, featureless, pulsating arc of aurora from last night. Credit: Bob King

A featureless auroral arc slowly pulsed in brightness low in the northern sky last night March 20. Credit: Bob King

I also wanted to revisit the aurora, which we’ve been revisiting for days now, since it won’t quit! Last night’s weird, pulsating patches continued through at least 3 a.m. this morning, and the space weather experts predict more minor storming early tonight and Sunday night. We’re stuck in an awesome auroral groove fueled by streams of electrons and protons whooshing from the holes in the Sun’s corona unconstrained by solar magnetic fields.

No complaints here!

Weird “teardrop” aurora airbrushes the first night of spring

Peculiar teardrop-shaped auroral patch in the northwestern sky this evening near the Pleiades star cluster (upper left). Credit: Bob King

Peculiar teardrop-shaped auroral patch in the northwestern sky this evening near the Pleiades star cluster (upper left). The aurora slowly pulsated in brightness. Credit: Bob King

Just got back from looking at some pretty weird northern lights. A bright teardrop-shaped patch glowed alone low in the northwestern sky around 10:30-11 p.m. 10 minutes later, another oval patch mysteriously appeared in the north. The two swelled in size and length and almost appeared to join … but didn’t . Instead, the teardrop faded away while the oval brightened. Then it slowly disappeared. When I last looked, the oval had returned but was fainter.

The teardrop on the left and oval to the right. Each slowly pulsed, fading and brightening. Credit: Bob King

The teardrop on the left and oval to the right. Each slowly pulsed, fading and brightening. Credit: Bob King

To look at the aurora indicators we’ve tapped into the past few nights — the  Kp index and auroral oval — you’d think there’d be no reason to don hat and coat and go aurora-hunting on cold, windy night. Both indicators are nearly flat, having dropped from minor storm level during the late afternoon (CDT). Yet Earth magnetic bubble keeps on jiggling, shaking out some peculiar forms of aurora.

A closer look at the featureless northern lights oval seen around 11 p.m. in the northern sky. Credit: Bob King

A closer look at the featureless northern lights oval seen around 11 p.m. in the northern sky. Credit: Bob King

One hint that solar excitement still lingers in Earth’s vicinity comes from the live information sent to us by the Advanced Composition Explorer (ACE) satellite, which taps into the Sun’s wind a million miles upstream of our planet. Around 10:30 p.m. (CDT), ACE recorded a southward dip in the magnetic field embedded in the solar wind – perfect for linking into Earth’s field and firing up auroras.

As always, it’s hard to know how long these “glows” may last, but if you’re out, don’t be surprised if you see them. We’re now at five nights in a row and counting for northern lights displays this week. Looks like we’re in for more. The forecast calls for yet another G1 geomagnetic storm Saturday evening (March 21) from about 7-10 p.m. CDT.