Train of Sunspots, November 4, 2015. Credit: James Guilford
An impressive train of sunspots has been making its way across the face of our nearest star this week. In the photo above: Designated AR2447 (small group to the left), AR2443 (bigger and darker, near center), and AR2445 (far right), the “Active Regions” have the potential of unleashing flares. In fact, AR2445 was the source of a flare that caused this week’s “northern lights” sighted across northern latitude locations around the world. Now rotating over the Sun’s limb, AR2445 won’t be aimed at Earth for a while — if ever again — but AR2443 has potential for high-energy flares.
Photo credit: James Guilford. Canon EOS 7D II: ISO 400, f/11, 1/1250 sec., 400mm lens with Astrozap film solar filter, heavily cropped, November 4, 2015.
Auroral display over Lake Erie. Photo by Christopher Christie.
A group of CAA members took advantage of beautiful night sky conditions to set up and observe from Medina County Parks’ Letha House Park — site of our Observatory. Among them was Christopher Christie. “I got home about 2:00 AM after a great, but cold night out at Letha House” he wrote. “I was starting to wind down around 3:00 AM when I noticed the Kp index was kicking up as the solar wind increased, it wasn’t much at the time but I kept an eye on it.”
He kept tabs on the situation. “About 3:30 the KP was up at 6, so I went to my front porch and didn’t see anything, but checked some of the other sites I use to check on the aurora and one showed a possibility of some moving in. So I went to the lake shore just inside Rocky River, and, well after about an hour and 175 images or so I was very happy.” We’re pretty pleased to see his results.
Auroral display over Lake Erie. White light at left-horizon is a passing boat. Photo by Christopher Christie.
It turns out Christie had tapped into the beginning of a big geomagnetic storm. By Saturday afternoon SpaceWeather.com was reporting that the storm continued to light the skies over nighttime areas of the globe and was expected to be active through Saturday night. Of course Saturday night brought clouds and rain to the Greater Cleveland Area. Still, it was a noteworthy event.
SpaceWeather.com explained, “The ongoing storm was triggered by a knot of south-pointing magnetism from the sun. During the early hours of Oct. 13, the knot bumped into Earth’s magnetic field, opening a crack in our planet’s magnetosphere. Solar wind poured in to fuel the auroras.”
At the bottom edge of the setting Sun, here, there may be a green flash.
The “green flash” is not a new Marvel Comics superhero but a subtle and interesting phenomenon sometimes seen just before sunrise or just after sunset; a green-colored ray or spot is seen just above the horizon. CAA member Jay Reynolds observed and photographed an occurrence of the green flash on Aug. 6 from Kelleys Island.
“Unfortunately, as these predictions go, the possibility of seeing it was well announced by TV meteorologists…” said Reynolds, “but this occurrence was subtle and not easily detectable.” In other words, many looked for the flash but few saw it!
“In photo number one, there is a possible green flash visible at the bottom of the sun. It is unfortunate that the shot is overexposed to the point of saturation” he said. “Suzie Dills deserves the credit for detecting it during the photo review.”
Green flash is visible just after sunset August 6, 2012. Enlarge to best see color.
“Photo number two is the best of the main sequence,” said Reynolds of his images. Viewed in a larger size, the green coloration is easily visible.
“It still was an outstanding Lake Erie Sunset shared by all!”
Just below center-left, is AR1520, as seen from Northeastern Ohio on July 12 at 6:18 PM EDT.
Dominating the face of our Sun, this week, has been an enormous group of sunspots including those designated AR1520. The active Sun has been very interesting to watch, of late, as the dark spots rotated over the star’s limb and towards the center of its disk, facing Earth. Hydrogen-alpha observers have also been rewarded with good numbers of prominences spouting into the blackness of space. Forecasters stated AR1520 had great potential for flare activity and on Thursday, July 12, the forecast was fulfilled — just as the sunspot was aimed directly at Earth.
According to SpaceWeather.com, “Big sunspot AR1520 unleashed an X1.4-class solar flare on July 12th at 1653 UT. Because this sunspot is directly facing Earth, everything about the blast was geoeffective. For one thing, it hurled a coronal mass ejection (CME) directly toward our planet. According to a forecast track prepared by analysts at the Goddard Space Weather Lab, the CME will hit Earth on July 14th around 10:20 UT (+/- 7 hours) and could spark strong geomagnetic storms. Sky watchers should be alert for auroras this weekend.”
NASA’s orbital solar observatories, of course, captured images of the flare as it erupted. Very rarely is any individual human observer watching when the detonation occurs but one can get lucky. CAA Vice-President Mike Williams was very lucky. “I was looking at the spot {with my personal solar telescope} when it popped,” he said. “Wow what a sight!”
As so often seems the case, weather forecasts for the weekend include plenty of clouds to interfere with the view. Still, aurora fans should stay alert to active displays and the potential for clear skies; it could be a good show!
UPDATE: The CME impacted the Earth’s magnetic field at ~ 1800 UT or 2:00 PM EDT, July 14.
Photo above: The Sun with prominent AR1520 accompanied by smaller sunspots. Canon EOS 50D: ISO 400, f/11, 1/1000 sec., 400mm telephoto lens with AstroZap white light filter, 6:18 PM, July 12, 2012 — “just before the clouds rolled in,” according to photographer James Guilford.
CAA: Cuyahoga Astronomical Association 