Thursday, August 24, 2017

The Great American Eclipse of 2017

Total solar eclipse, August 21, 2017, from Greer, SC.
Various circumstances came together this week, so that I was able to drive south and stay in the Asheville, NC area, within easy striking distance of the path of totality through South Carolina for Monday's solar eclipse. I headed to Greer, SC, where there was an eclipse viewing event in the city park.
Some of the crowds at Greer City Park.
Traffic getting down to the Carolinas from the Northeast on Sunday was pretty heavy, though a couple of hours added onto a 15 hour drive wasn't a huge deal. On the state roads to Greer Monday morning, there were quite a few cars heading into the path of totality, but things moved along and there wasn't too much trouble finding parking. The parks department had some entertainment going and was handing out eclipse guides and solar viewing glasses. The area near the food trucks and such was crowded, with lawn chairs and picnic blankets packed into every patch of shade, so I headed for another section of the park that was pretty lightly populated.

My cheesy projection system.
In addition to the solar glasses, I had some pinhole viewers, which worked but made kind of small, pale images. I also jury-rigged a projector with binoculars tied with string to a tripod, which made nice, bright images that included smaller details like sunspots that were invisible with the glasses, but which was unstable and needed a lot of fiddling to keep working. I should have put in more preparation: if the binoculars were firmly affixed to the tripod and there was a shade blocking the sun around the lenses, it would have been much more useful.
Getting darker, near the bandstand. I think the camera didn't really know what to do with the exposure at this point.
There were scattered clouds around in the morning, but as the eclipse progressed they got thinner and finally pretty much disappeared for the main event. This is a fortunate effect of the weakening of solar heating of the air, causing atmospheric convection to dissipate, as the moon blocks more and more light.

A photo through solar glasses, with some thin remaining clouds over the sun.
During the darker phases of the three hours of the eclipse, the air temperature noticeably cooled. It was quite a pleasant change from what had started out as a hot, steamy morning with scorching sun. People starting moving out from under the trees and out onto the open lawns.

Crescent images of the sun under a tree.
One of the well-known eclipse lighting effects is that splotches of sunlight under trees take on the shape of the crescent sun. Actually, dappled light under trees always includes images of the sun focused by diffraction between leaves, but these are normally round and unchanging, and go generally unnoticed as just part of the way the natural world always looks. Especially as totality is getting near, shadows get weirdly sharp, and include little crescent shapes along their edges.

Clouds disperse and the parks lights flicker on as totality gets close.
About 15 minutes on either side of totality, it was dark enough that street lights came on. Animal life started reacting, too, and some kind of loud nocturnal insect (a southern katydid?) started singing from the trees.
The sky is getting dark and a crow flies overhead.
Birds were affected as well. In particular, I noticed crows flying singly and in small groups, all on the same course, the way they normally do in the evening when they are heading to their roost. In the final seconds before totality, the "shadow bands" effect was visible on the sidewalk, with stripes of light and dark rapidly running across the landscape

The park at totality, with sunset-like light all around the horizon.
Totality itself was as amazing as promised. One astronomer I caught on NPR on the drive down said something to the effect of "seeing a 99% eclipse is like taking a family trip 99% of the way to Disney Land," and I'd guess that's probably about right. The million-degree plasma of the corona is sort of a ghostly grey-blue-violet that doesn't really occur elsewhere, and even pro photographs don't do it justice, let alone my quick snapshot at the top of the post. That contrasts with the outline of the moon, which looks, at least in comparison, to be an absolute dead black. Some other celestial objects were theoretically visible at totality, but the only one that I noticed was a blue point, almost within the corona, that was apparently the star Regulus. Venus must have been easily visible, but I wasn't aware of it because I was focused so intently on the eclipse. Totality lasted about 1.5 minutes in Greer, but it seemed like it was over in about 10 seconds to me. The big show finished with a supremely brilliant "diamond ring" effect as a tiny point of the sun's surface reappeared.

The shadow bands had started up again when I turned away from the sun, with the bands running in a different direction than they had been moving before totality. I waited around Greer for a bit after the eclipse, while people cleared out, but there was still a certain amount of traffic even on the back roads returning to North Carolina. That evening I thought to check out the traffic function on Google Maps, and there was an obvious wave of traffic jams spreading out on the highways from the midline of the eclipse, all across the country.

A wild ginger, probably Asarum arifolium.
I hung around the foothills of the Smokey Mountains for another couple of days, and did get a chance to get out into the woods a bit. In steep, damp ravines I saw some interesting smooth-leaved wild gingers, not the familiar Asarum virginicum.

Kudzu, Pueraria montana, the vine that ate the South.
I flew back north on Wednesday, and there were still others traveling who had been in the area eclipse-watching, carrying tripods and talking about the wonders of totality. The lines at the smallish Spartanburg airport were probably considerably longer than they normally are in the middle of the week, but I got through security with time to spare and was back in Connecticut in time for dinner.