LAST NIGHT IN ICELAND: No solar activity, no problem. The gentle buffeting of the solar wind continues to be enough to spark auroras around the Arctic Circle. Here was the scene last night in Iceland:
"Bright moonlight lit up the night like midday," says photographer Jónína Óskarsdóttir of Faskrudsfjordur, Iceland. "Nevertheless, the auroras were plainly visible."
The waxing Moon will brighten furthern tonight. Will the Northern Lights continue to penetrate the glare? Stay tuned: NOAA forecasters estimate a 25% chance of polar geomagnetic storms on Feb. 22-23. Aurora alerts: text, voice.
Realtime Aurora Photo Gallery
TWO COMETS AND THE SOUTHERN LIGHTS: Two comets are now visible in the skies of the southern hemisphere: "Comet Lemmon and Comet PanSTARRS got close enough together on the morning of Feb. 17th to fit into single image with a 35mm lens," reports Alex Cherney of Flinders, Victoria, Australia. "A brief but reasonably strong aurora was a welcome bonus." Click to set the scene in motion:
"Both comets were faint but visible to the naked eye, C/2011 L4 (PanSTARRS) slightly brighter than C/2012 F6 (Lemmon)," says Cherney. "I would guestimate the visual magnitude of Comet Lemmon at +5.5 and PanSTARRS at +5." Also visible in Cherney's images are the Small Magellanic Cloud and the 47 Tuc globular star cluster.
Comet Pan-STARRS is heading for a close encounter with the sun just inside the orbit of Mercury that could significantly boost its visibility in early March. At that time, the comet will be visible to northern-hemisphere observers as well. A video from NASA explores the possibilities.
More about Comet Lemmon: 3D orbit, ephemeris, light curves; and Comet Pan-STARRS: 3D orbit, ephemeris, light curves.
Realtime Comet Photo Gallery
FARSIDE CME: There is an active sunspot on the farside of the sun. Yesterday, Feb. 25th, it blasted a coronal mass ejection (CME) over the sun's northwestern limb, shown here in a movie from the Solar and Heliospheric Observatory:
A 3D model of the CME prepared by analysts at the Goddard Space Weather Lab shows that the CME will miss everything--no planets are in the line of fire.
NASA's STEREO-Ahead spacecraft is stationed over the farside of the sun, almost directly above the CME. Images from the spacecraft pinpointed the source of the blast: It is active sunspot AR1678, which rotated off the Earthside of the sun just a few days ago.
Realtime Space Weather Photo Gallery
CORONAL HOLE: A dark gap in the sun's atmosphere--a "coronal hole"--has opened up, and it is spewing a stream of solar wind into space. NASA's Solar Dynamics Observatory (SDO) photographed the opening during the early hours of Feb 24th:
Wondering about the colors in this image? This is how the sun looks through SDO's extreme UV filters.
Coronal holes are places where the sun's magnetic field opens up and allows the solar wind to escape. A stream of solar wind flowing from this particular coronal hole is expected to reach Earth on or about March 2nd. High-latitude sky watchers should be alert for auroras on that date. Aurora alerts: text, voice.
Bonus: The image also shows the magnetic canopy of a sunspot group approaching just beyond the sun's northeastern limb. The active region should emerge in the next 24 hours.
GEOMAGNETIC DISTURBANCES: A high-speed solar wind stream is buffeting Earth's magnetic field, sparking bright auroras around the Arctic Circle. The sight of the bright green lights overhead is causing some onlookers to do unusual things in the snow:
"I can honestly say I've never seen anyone do The Pyramid under the Northern Lights before," says veteran aurora photographer Ronn Murray of Fairbanks, Alaska. "[On March 1st], I headed up to the top of Murphy Dome with this incredibly fun tour group. We had a blast making portraits under the aurora. The clouds would eventually take over, but we made the most of the show while it lasted."
More auroras are in the offing. NOAA forecasters estimate a 30% to 45% chance of polar geomagnetic storms on March 2-3 as the solar wind continues to blow. Aurora alerts: text, voice.
COMET PAN-STARRS UPDATE: Comet Pan-STARRS, now visible in the southern hemispherre, is brightening as it plunges toward the sun, Amateur astronomer Ian Cooper sends this report from Glen Oroua, New Zealand: "Despite lingering evening twilight and the glare from a nearly full Moon, Comet Pan-STARRS is a 3rd-magnitude object with a fine orange dust tail visible in both binoculars and small telescopes." A 30-second exposure with his Canon 450D digital camera easily revealed the comet in the not-quite-dark sky:
In early March, the comet will pass about 100 million miles from Earth as it briefly dips inside the orbit of Mercury. At that time it is expected to brighten another three-fold to 2nd magnitude, about as bright as the stars in the Big Dipper. Whether Pan-STARRS will actually be visible to the naked eye through the glow of the nearby sun remains to be seen; this NASA video explores the possibilities. Whatever happens, observers in the northern hemisphere will have a front row seat as the comet crosses the celestial equator on March 12th. Stay tuned!
More about Comet Pan-STARRS: 3D orbit, ephemeris, light curves.
PHOTO-OP TONIGHT: Tonight, March 12th, Comet Pan-STARRS (C/2011 L4) is getting together with the slender crescent Moon for a beautiful sunset conjunction. The only question is, will you be able to see it? Naked-eye observers are having trouble finding the comet in bright twilight. The good news is, it only takes a couple of seconds of exposure time to produce a picture like this:
"This is a 2-second exposure I made using my Canon 2Ti digital camera set at ISO 800," says Russell Vallelunga of Phoenix, Arizona. "Comet Pan-STARRS was even more impressive tonight (March 11th) than last night, being much higher in the sky."
Add the crescent Moon to this scene and presto! -- a fabulous photo-op. Look low and west after sunset for the Moon and Pan-STARRS only a few degrees apart. Let the Moon guide you to the comet; it is visible to the naked eye if you know where to look. Binoculars are helpful, too. Sky maps: March 12, March 13.
More: NASA video, 3D orbit, ephemeris, light curves.
MAGNETIC ERUPTION ON MARCH 12th: A magnetic filament in the sun's northern hemisphere erupted today, March 12th, around 1107 UT. Extreme ultraviolet telescopes onboard NASA's Solar Dynamics Observatory recorded the action:
The source of the explosion was active region AR1690 on the sun's central meridian. Although AR1690 is almost directly facing our planet, debris from the blast might miss Earth. A CME emerging from the blast site appears to be heading mostly north of the sun-Earth line. Stay tuned for updates about a possible glancing blow in 2-to-3 days. Aurora alerts: text, voice.
WILL THE SKY TURN GREEN ON ST. PATRICK'S DAY? A magnetic filament snaking around sunspot AR1692 erupted on March 15th at about 0600 UT. The slow explosion, which took hours to unfold, produced an M1-class solar flare and a bright CME. SOHO (the Solar and Heliospheric Observatory) photographed the expanding cloud, which is heading directly toward Earth:
The CME left the sun traveling some 900 km/s (2 million mph). Three-dimensional computer models based on observations from SOHO and NASA's twin STEREO probes predict the CME will cross the void between sun and Earth in two days or less. NOAA forecasters estimate a 70% chance of polar geomagnetic storms when the cloud arrives on March 17th. This means the sky could turn green on St. Patrick's Day! High latitude (and possibly even middle latitude) sky watchers should be alert for auroras this weekend. Aurora alerts: text, voice.
THE MAGNITUDE OF COMET PAN-STARRS: "There seem to be a lot of pictures, but a shortage of magnitude estimates for Comet Pan-STARRS," says Richard Keen, professor of atmospheric sciences at the University of Colorado. "I saw it for the first time this evening, and got a magnitude estimate before the comet slipped behind a narrow cloud bank." Keen is an expert observer of astronomical brightness, especially that of lunar eclipses which he uses to study aerosols in the stratosphere. "The comet is magnitude +0.2 with a short, but bright vertical tail. It was quite visible to the unaided eye. After the [head of the comet] set behind the mountains, the tail was visible for two or three more minutes."
A growing number of observers say they can see the comet with their unaided eye. Here it is on March 14th at sunset over Valley Forge, PA:
"The comet looked fantastic through my 10x70 Fujinon binoculars, and it was barely visible to the naked eye," says photographer John Chumack. Note: "Barely visible" is an improvement over recent nights.
Visibility should continue to improve in the nights ahead as Pan-STARRS moves away from the sun. Keen's magnitude estimate of +0.2 means that the comet is approximately twice as bright as a first magnitude star. When it is framed by darker skies, it will really stand out. Tonight when the sun goes down, step outside, face west, and take a look: sky map.
More: NASA video, 3D orbit, ephemeris, light curves.
ST. PATRICK's DAY CME IMPACT: As predicted, a CME hit Earth's magnetic field at 0600 UT on March 17th. The impact sparked a moderately strong (Kp=6) geomagnetic storm that sent Northern Lights spilling across the Canadian border into the United States as far south as Colorado:
"Just after 4 am local time, the skies turned green and red behind the twin stone monoliths of Rabbit Ears Peak near Steamboat Springs," reports photographer Jimmy Westlake, an astronomy professor at Colorado Mountain College.
In the contiguous United States, auroras also appeared above New York, Washington, Minnesota, Wisconsin, Wyoming, Michigan, the Dakotas and elsewhere. Scan the realtime photo gallery and count the states.
COMET PAN-STARRS UPDATE: As it emerges from the glare of the evening sun, Comet Pan-STARRS is becoming even more photogenic. Last night, March 17th, Alan Dyer caught it setting behind the Very Large Array, a radio telescope in Socorro, New Mexico:
Movie-goers will remember seeing the VLA in Carl Sagan's movie Contact starring Jodie Foster. Among astronomers, the array is even more famous for real-life scientific discoveries. On March 17th, the great telescope was window dressing for a comet.
"Light from the nearly quarter Moon high in the sky illuminated the landscape and highlighted the rims of the 27 dishes of the VLA," says Dyer. "Fortunately, the array was arranged in its most compact formationfor easy photography – at times the dishes can be spread out over many miles."
"The comet appeared in deep twilight," he continues. "A classic curving dust tail is now obvious in photos. This comet will bear watching and shooting over the next month, no matter where you are in the northern hemisphere."
For casual sky watchers: A growing number of people are reporting that they can see Comet Pan-STARRS with the naked eye. Best estimates place the magnitude of the comet at +0.2, about twice as bright as a 1st magnitude star. As the comet moves away from the sun, its visibility is improving. Observing tip: Step outside about an hour after sunset and face west. Pinpoint the comet using binoculars. Once you know where to look, put the optics aside and try some naked-eye observing. [sky map]
ST. PATRICK's DAY CME IMPACT: As predicted, a CME hit Earth's magnetic field during the early hours of March 17th, sparking a geomagnetic storm (Kp=6) and bright auroras at high latitudes. "What a great and green way to begin St. Patrick's Day!" says Dennis Mammana, who sends this picture from Fairbanks, Alaska:
"The CME kept us aurora photographers hopping all night long," says Mammana. "The only reason I gave up around 2 a.m. is that I ran out of memory cards for my digital camera! One of the most lovely auroral shapes--the corona--occurred one after the other after the other and was one of the prettiest displays Ive seen in many years."
The storm is subsiding now, but more auroras could be in the offing. A solar wind stream is due to brush against Earth's magnetic field on March 19-20. The impact won't be as strong as that of the March 17th CME. It should be enough, however, to spark some more Arctic lights. Aurora alerts: text, voice.
DOUBLE FLARE THREAT: Two sunspots now facing Earth pose a threat for geoeffective flares. AR1731 has a 'beta-gamma' magnetic field that habore energy for M-class flares, while AR1730 has a 'beta-gamma-delta' magnetic field capable of unleashing even stronger X-class flares. NASA's Solar Dynamics Observatory recorded the growth of these sunspots over the past 48 hours:
NOAA forecasters estimate a 5% chance of X-flares today, April 30th. Normally, X-flares are common around the peak of the solar cycle, yet there has not been a single X-flare all year. Perhaps we're overdue; stay tuned! Solar flare alerts: text, voice.
Coronagraph images from NASA's twin STEREO probes confirm that a CME emerged from the blast site. Earth was not in the line of fire. Next week, however, we might be as the sun's rotation turns the active region toward our planet. Stay tuned for updates. Solar flare alerts: text, voice.
"RING OF FIRE" SOLAR ECLIPSE: As the sun rose over Australia on Friday morning, May 10th, the solar disk turned into a ring of fire. The day began with an annular solar eclipse:
Nicole Hollenbeck took the picture from inside the narrow path of annularity about 70km south of Newman, Australia. At the time, more than 95% of the sun's diameter was covered by the Moon.
In an annular eclipse the Moon is not quite big enough to cover the entire solar disk. A blinding ring of solar fire juts out around the Moon, overwhelming the sun's delicate corona. It may not be the same as totality, but annularity has a charm and beauty all its own. Browse the gallery for more images from the eclipse zone.
Realtime Solar Eclipse Photo Gallery
SPECTACULAR PROMINENCE, GONE: For the past few days, astronomers around the world have been monitoring a bushy filament of magnetism dancing along the sun's western limb. Sergio Castillo of Inglewood CA photographed the structure on May 9th just before it collapsed:
"OMG! This giant prominence was one of the most spectacular I have ever witnessed," says Castillo. "Yesterday, however, it collapsed on its own magnetic field and nothing remains of it."
The filament has disappeared from the sun, but all 250,000 km of it may still be found in the space weather photo gallery. Start looking.
ICE HALO AROUND THE SUN: On May 6th, Daryl Pederson went to Point Woronzof in Anchorage, Alaska, to see the USS Anchorage depart. "But," says Pederson, "the sun refused to be outshone." Instead of photographing the amphibious warship, he recorded this complex ice halo in the sky overhead:
The luminous arcs and rings around the sun are caused by sunlight shining through ice crystals in thin, high clouds. Usually only one or two of these ice halos appears at once, but Pederson caught at least 6 different varieties, identified and labeled above by atmospheric optics expert Les Cowley.
"It is sometimes hard to believe that tiny ice crystals floating in the air or clouds can make such precise and beautiful sky geometry," comments Cowley. "Two reasons:- One, the small crystals unlike their larger and more familiar snowflake cousins are near optically perfect. Two, they are set firmly in near perfect alignments by aerodynamic drag forces as they drift slowly down relative to local air currents. Only the circular 22o halo comes from tumbling crystals and they generate geometric perfection, too!"
More optical perfection may be found in the space weather photo gallery. For those who came in late, I'll remind all this is from the Spaceweather site and is placed here for logging significant events for future study by anyone who wishes to compare my own or their work against these events. The links are to Spaceweather sites, thus their free plug.
THE SHOW BEGINS: The long-awaited sunset sky show of May 2013 is beginning. In only a few days, Venus, Jupiter and Mercury will form a tight triangle in the western sky, visible to the unaided eye around the world. Last night, Fred Espenak of Portal, Arizona, photographed the trio in the early stages of convergence:
"The three planets were easily visible to the naked eye in spite of the bright twilight glow," says Espanel. "Mercury should be even easier to spot in the coming days as it climbs higher into the sky. "
In the nights ahead, the line of planets will collapse to form a triangle. At closest approach on May 26th, they will fit within a circle less than 3o wide. Start watching tonight--it's a great way to end the day. [full story] [video]
A BIG ASTEROID APPROACHES: Near-Earth asteroid 1998 QE2 is approaching the Earth-Moon system for a flyby on May 31st. There's no danger of a collision; at closest approach the asteroid will be 3.6 million miles away. Even at that distance, however, the 1.7-mile-wide space rock will be an easy target for mid-sized backyard telescopes. Using a 14-inch Celestron, Alberto Quijano Vodniza of Narino, Colombia took this picture of 1998 QE2 on May 17th:
The sunlit side of the asteroid will turn more squarely toward Earth during the first week of June. At that time it will reach a maximum brightness of 11th magnitude.
NASA radars will be monitoring the flyby, too. "Asteroid 1998 QE2 will be an outstanding radar imaging target at Goldstone and Arecibo and we expect to obtain a series of high-resolution images that could reveal a wealth of surface features," says radar astronomer Lance Benner of JPL. "Whenever an asteroid approaches this closely, it provides an important scientific opportunity to study it in detail to understand its size, shape, rotation, surface features, and what they can tell us about its origin."
Stay tuned for updates and observing tips.
CORONAL HOLE: A hole in the sun's atmosphere--a "coronal hole"--has opened up and it is spewing solar wind into space. NASA's Solar Dynamics Observatory photographed the UV-dark gap during the early hours of May 29th:
Coronal holes are places where the sun's magnetic field spreads apart and allows solar wind to escape. A windy stream of plasma flowing from this particular hole should reach Earth on June 2-3. The impact could spark geomagnetic storms and auroras around the poles. Aurora alerts: text, voice.
AN OUTBREAK OF MAGNETIC FILAMENTS: The sunspot number may be low, but the sun is far from blank. Amateur astronomers monitoring the sun report a large number of magnetic filaments snaking across the solar disk. Sergio Castillo captured more than half a dozen in this picture he sends from his backyard observatory in Inglewood, California:
"Filaments are popping up all over the solar surface," says Castillo. "Each one has a unique shape and length."
The longest one, in the sun's southern hemisphere stretches, more than 400,000 km from end to end. "It's one of the longest filamentary structures I have ever seen," says veteran observer Bob Runyan of Shelton, Nebraska.
If any of the filaments collapses, it could hit the stellar surface and explode, producing a Hyder flare. Filaments can also become unstable and erupt outward, hurling pieces of themselves into space. Either way, astronomers with solar telescopes are encouraged to monitor developments.
GAMMA DELPHINID METEORS: On June 11, 1930, Earth passed through a stream of debris from an unknown long-period comet, producing a flurry of gamma Delphinid meteors. Two days ago, on June 11, 2013, researchers said it might happen again. It didn't; the expected outburst failed to materialize. Nevertheless, a small number of candidate gamma Delphinids were seen by observers around the world. Yuri Beletsky captured these over the Las Campanas observatory in Chile:
"Meteor activity was lower than expected," says Beletsky. "Even so, we saw a few of them."
Thomas Ashcraft also recorded a spectacular gamma Delphinid over his private observatory in rural New Mexico: movie. "The fireball appeared ten minutes from the predicted outburst peak time," notes Ashcraft.
"It is still possible that we glanced the dust trail and caught a few meteors," says Peter Jenniskens of the SETI Institute, one of the forecasters who predicted the return of the gamma Delphinids. "At 8:32 UT, I myself saw a short bright +1 meteor radiate from Aquila in a clearing between clouds at Lick Observatory. Sadly, other sites of our video camera network were clouded out. Given that the shower's radiant may have been at a different location [compared to 1930], please do keep collecting photographs of meteors taken that night. Single-station photographs may yet identify a compact radiant. Once we know the radiant, we can make more accurate predictions for the future. "
Realtime Meteor Photo Gallery
AURORAS + NOCTILUCENT CLOUDS: On Sunday, June 9th, Alan Dyer of Gleichen, Alberta, Canada, went outside to see the colors of the sunset. He got more than he bargained for. Stacked atop the rosy glow of twilight were dual bands of electric-blue noctilucent clouds and green auroras:
"At times the auroral curtains appeared superimposed on the noctilucent clouds," says Dyer. "It isn't often we see the two phenomena together."
That's because they are completely unrelated. Auroras are caused by energetic particles from the sun raining down on Earth's upper atmosphere, causing the air to glow like the picture tube of a color TV. Noctilucent clouds are made of tiny ice crystals wrapped around bits of meteor smoke. Their electric-blue color comes from the scattering of high altitude sunlight. On June 9th the two phenomena overlapped for a rare display.
"Adding to the colours was the deep orange of perpetual twilight rimming the northern horizon," continues Dyer. "It was a beautiful pre-solstice night."
More aurora-noctilucent overlaps might be in the offing. NLC experts say noctilucent clouds have appeared bright and early this year, while 2013 might bring the late surge of a double-peaked Solar Max. High-latitude sky watchers should keep an eye on the sunset. Aurora alerts: text, voice.
Realtime Noctilucent Cloud Photo Gallery
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