AR1520 gets even more interesting

The Sun with Sunspot AR1520 and Company, July 12, 2012 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.”

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!

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.

Truly memorable sunspot

Sunspot group AR1520 as it appeared July 11, 2012. Blame image softness on the photographer!

Hosting a group of kids from Camp Asbury church camp this morning, we were treated to the best views of sunspots I’ve ever had. Sunspot group AR1520 is absolutely enormous, dominating the face of the Sun and observing conditions were very good. We could see good detail within the sunspots and where they merged along with some hints of granulation. We viewed the Sun at about 30X and, later, at 139X through Stephens Memorial Observatory’s 112-year-old 9-inch refractor fitted with a white light solar filter. We had 15 day campers (grades 1-6) and seven staff for a total of 22 people. I'm sure at least a few of them will remember AR1520 and our grand, old telescope for a long time to come! In the front yard we had our little hydrogen-alpha telescope set up. The views were less impressive but, if the viewer knew just what to look for, there were many prominences visible around the Sun's limb; old Sol is really active this summer!

After the campers left I hauled out my camera and discovered I had the wrong direct-focus adapter (1.25-inch instead of 2-inch) with me and could not focus at all! So I removed a piece to shorten the distance to the camera's focal plane, focused as best I could, and hand-held the camera at the open telescope tube for a direct-focus image. A yellow filter is in place within the camera adapter to try and keep the sensor clean. The resulting image is soft, not doing justice to the telescope or the sunspots, but the view is impressive nonetheless; it’s a good representation of what we saw, which was truly amazing!

Image Notes: Canon Digital Rebel XT: ISO 400, 1/1000 sec., yellow filter; handheld direct-focus image using 3,327mm refracting telescope (Warner & Swasey, circa 1901) with white-light solar filter by AstroZap.