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, 2:22 PM.
Our Sun is just past the peak of its 11-year activity cycle but has been unusually quiet of late. Many days we have seen few, if any, sunspots marking the star’s face. Over the past few days, however, there has been an uptick in activity including the passage of large sunspot region AR2339 (lower-right in our photo). The sunspot has been the source of major solar flares including one that interfered with radio communications in the Pacific region. This image is a single exposure made using a digital SLR camera held to the eyepiece of the Cooley Telescope at Stephens Memorial Observatory. A white-light filter was used for the protection of equipment and vision. A good article on the current solar cycle can be found here.