The Sun, showing several sunspots/active regions. This image was made at 3:43 PM EDT/7:43 PM UTC on September 10, 2021 using the photographer’s personal reflecting telescope with safe solar filter, and DSLR camera body. Credit: James Guilford
After a long period of quiet during our Sun’s fairly predictable 11-year activity cycle, things have been happening. What was a bright, clear disk has become speckled with sunspots of late. The increased activity brings with it the chance of Earth-directed coronal mass ejections, or CMEs, which result in solar storms when they collide with our home planet’s magnetic field. Auroras, or “northern lights” for us, are one potential result of solar storms. The less pleasant effects can include disruption of radio communications and satellite operation, all the way to electrical grid failures at the extreme!
Several recent CMEs have missed Earth but one is headed in our direction as this blog entry is being written. According to SpaceWeather.com, “{A} CME is on the way following an explosion in the magnetic canopy of sunspot AR2864 on Sept. 8th. NOAA analysts believe Earth could experience a glancing blow or near miss late on Sept. 11th.” Those favored with clear skies and a good view to the north may want to be on the lookout for aurora, but the odds aren’t favorable … this time!
Here are two photos of Sun, shot by Stephens’ Director James Guilford, at 3:43 PM EDT (7:43 PM UTC). The first image shows the full solar disk. Notice not only the dark sunspots but also the lighter-colored “splotches” of additional active solar regions, most visible near the edges of the disk.
The second image is cropped to show the major concentration of the day’s sunspots with their official numerical designations. Both images have been color tinted.
A tightly-cropped portion of the day’s full-disk image shows three sunspot groups: AR 2866, AR 2868, and AR 2869. Sunspots only appear to be dark because they are significantly “cooler” than the surrounding solar atmosphere; they are actually quite hot. Sun’s shining photosphere has a temperature of 5,800 degrees Kelvin while sunspots have temperatures of around 3,800ºK (6,380℉). Nearly all of the dark features seen here are larger than planet Earth. Credit: James Guilford
The partial solar eclipse reaches its maximum at 2:23 PM EDT as viewed from Hiram College, Hiram, Ohio
On Monday, August 21 millions gathered along a thin path crossing the United States to watch a total eclipse of the Sun, the first to cross the continent since June 1918. Those with favorable viewing conditions along the path of totality enjoyed a truly amazing sight and experience; a total solar eclipse is truly awe-inspiring. From Northern Ohio, outside of the eclipse path, 80 percent of the solar disk would be covered by the Moon. Public interest in the event was high and so we hosted the Hiram Eclipse Watch
Watching and Waiting for the Big Event – Credit: James Guilford
We estimate at least 375 people came to the campus lawn to share nature’s show and enjoy the sight together. Some families brought blankets and had picnic lunch in the shade of trees while waiting for the eclipse to begin. Driven by media reports, demand for Sun-safe eclipse viewing glasses was tremendous. Hiram had 300 eclipse viewers available for free distribution and even with restriction to one viewer per family or group, we ran out of glasses long before the eclipse ended. The offer of free eclipse glasses did, however, encourage some of our attendees to come out to Hiram College and discover there was more to enjoy than a giveaway; the view through our telescopes was tremendous.
Woman watches eclipse through specially-equipped telescope. Credit: Dave Dreimiller
Three telescopes offered safe views of the eclipsing Sun three different ways. One scope employed a glass filter with metal compounds that absorbed the Sun’s dangerous radiation and presented an orange-tinted image. The largest telescope present, a six-inch refractor, was outfitted with a modern version of the Herschel Wedge; that telescope focussed unfiltered light into the wedge which, in turn, deflected all but a small amount of light with a green tint and offered tack-sharp viewing of the disappearing Sun, sunspots, and granulation texture in the solar atmosphere. A third instrument was a telescope specifically made to view the Sun only hydrogen alpha (Ha) light. Ideally, an Ha scope will show details of the solar atmosphere invisible to those using other methods, and include solar prominences — geysers of plasma arcing high above the Sun — but none were seen this day.
Watching the Eclipse with Safety Glasses – Credit: Dave Dreimiller
People of all description came and went during the event though most stayed until the maximum eclipse had been reached and the Moon began to recede from Sun. Lines of folks waited patiently to see the telescopic views, even attempting smart phone photos; there were many repeat views, observing the progress of the eclipse with each fresh look. We estimate at more than 375 people came to the campus lawn to share nature’s show and enjoy the sight together.
Solar Telescopes Trained on the Eclipse – Credit: Dave Dreimiller
There was learning, and laughter, and a fine day shared under Sun and Moon. It may not have been a total eclipse for those watching from Hiram College, but it was a total pleasure.
Before Maximum Eclipse – Credit: James Guilford
Cooperative weather plus plenty of happy and excited people made the afternoon a wonderful occasion sharing a fine day featuring a dance by the Sun and Moon.
Before Maximum – Rough Edge. Look closely along the dark curve of the Moon moving over the Sun and note “bumps” along the edge: the silhouettes of craters and mountains on the Moon.
The (Ravenna) Record-Courier made it front-page news!
Changing a word from an old song lyric by The Police, there’s a big black spot on the Sun today. Sunspot AR2529 is the dominant feature on our otherwise quiet star. Visible to the unaided eye through solar-safe filters, the sunspot is several Earth-diameters across and roughly “heart” shaped! This image was recorded Wednesday, April 13, at 2:19 PM. The bright orange color resulted from use of a solar filter covering the camera lens.
Here is what SpaceWeather.com says about the sunspot: “Since it appeared less than a week ago, AR2529 has been mostly, but not completely, quiet. On April 10th it hurled a minor CME into space. That CME, along with another that occurred a few hours later, could deliver a glancing blow to Earth’s magnetic field on April 13th.” A CME is a Coronal Mass Ejection wherein the Sun flings plasma from its atmosphere out and into space. CMEs reaching Earth can cause auroras.
Photo (above) Info: Cropped from full frame, Canon EOS M3: ISO 250, 1/1600 sec., f/8, 400mm lens. Photo by James Guilford. Photo (below) Info: Canon EOS 6D: ISO 400, f/4, 1/1250 sec., observatory telescope afocal technique.
Sunspot AR2529 – April 14 – Through the Vintage Cooley Telescope
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.
Granular Sun – July 20, 2015Testing out a modified eyepiece adapter today, I had the vintage Cooley Telescope pointed at the Sun. Since everything was set up, I decided to see whether we could capture decent images of our nearest star, near noon on this clear summer day. While the sky was clear, the seeing — quality of the view — was not as good as I’d hoped. Apparently, midday heat was causing the image to “shimmer” in the eyepiece and the photographs reflected that. Examining the pictures on the computer screen, I was disappointed because I saw no details in the several sunspots visible. As I made some photographic adjustments, however, other features came into view: granulation and faculae! The granules, upwelling super-hot cells of solar atmosphere, are easy to see; they give the image above a “grainy” appearance. Faculae are a bit trickier but if you look along the darker right-hand edge of the solar image, you will see some light-colored patches — those patches are faculae! So a bit of disappointment changed to a sunny day surprise.
NOTES: Sunspots in this image are #2387 (L) and #2386 (R). For more information on the Sun’s photosphere and what can be seen there, visit this page at NASA/ Marshall Space Flight Center.
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.
Stephens Memorial Observatory 