It's two days after the eclipse, and we are still euphoric. We spent the rest of eclipse day packing up equipment, staying over at our Tianhuangping aerie. Bit by bit over the internet, we learned of other sites: it rained at one of the other sites that we had seriously considered (the coast near Shanghai) and was foggy at the other (Moganshan, at 300 m of altitude). Suzhou, were we are now, was rainy also. And Wuhan, the other big city in the path, hundreds of miles west, had visibility through clouds, as we had, though from photos, our site seemed a bit better. As I say to everyone every few hours, "we-were-incredibly-lucky!!"
Yesterday, the main part of our team of scientists and students came down the mountain, detouring by the "tidal bore," another phenomenon of nature. In a tidal bore, as the tide reverses a row of waves moves up river against the current. We have read that the tidal bore was 10 meters high here, the highest in the world, but then heard that yesterday's was "only" 1 to 2 meters high. Still, our group was mainly made of scientists (or scientists' families), and we went. And we were glad we did. It was interesting to see a surfable row of waves come up river, in view for 15 minutes before it reached us. It extended perhaps a kilometer, as far as the eye could see, across the wide estuary that leads from the Pacific west to Hangzhou. And then it left standing waves after it went by.
We next continued to the "packager," who was going to wrap up our equipment on a pallet so that UPS could bring it back to the US for us. Bryce Babcock, the Williams College physicist who had been in charge of our instrumentation, was told that they had never actually shipped a package to the US but they knew that they should be able to do it. We hope it arrives soon. I joked that we don't really need it until the eclipse in Australia in 2012, though, of course, we have lots of stuff on it that we do need soon after our return.
We all discussed next year's total solar eclipse, July 11th, 2010. The only substantial land from which it will be viewable is Easter Island, a Chilean island the size of Manhattan that is 2200 miles off the coast of Chile. We know that access is limited and that the airline involved and the hotels have raised their prices considerably. Still, many of us will be trying to go.
Bright and early this morning, July 24th, those of us who hadn't departed last night got on buses for Suzhou or for Pudong Airport in Shanghai. My wife and I were attending an international meeting of sponsored by the Chinese Academy of Sciences and the International Astronomical Union. I had stayed up last night working on my PowerPoint presentation, updated and modified from my Hangzhou science museum presentation with a half dozen images from totality and another half dozen from the partial eclipse. Our colleagues Mike Kentrianakis and Paul Rosenthal had made HD movies, and Mike edited the two diamond rings into about a 30-second digital film. We will be posting this film and various images at our eclipse website, http://www.williams.edu/Astronomy/eclipse/eclipse2009/
Three of our alumni, plus families, joined me at the Suzhou Conference Center after our two and a half hour chartered bus ride. My half-hour talk seemed to go well, and I answered a variety of questions from the audience. I ended with our diamond-ring movie and then left some satellite views of the eclipse moving across the Earth on the screen.
Last night, I had uploaded some sample eclipse images to a digital-media colleague at NASA's Goddard Space Flight Center, and he had sent me the composite image for me to improve the orientation of our eclipse image with respect to the satellite images from the Solar and Heliospheric Observatory. I approved it, suggesting that the little dots from cosmic-ray hits be cosmetically removed. It is appearing online, and I used it in my talk. The scientific result is that the corona is even sparser than expected. I had thought that last year's corona, at solar minimum, was weak, but this year's coronal streamers, in the continued solar minimum (75% of the days of the year have thus far had sunspot number equal 0) were even weaker. Further, the polar plumes seemed relatively sparse and faint. A corollary, seen in Aris Voulgaris's spectra as part of the Greek contingent's membership in our eclipse team, is that the iron-14 line, which has lost 4 more electrons through injection of energy than the iron-10 line, was all but undetectable. So the corona is overall cooler than even last year.
And we had one other pretty scientific result so far: the temperature data logger showed four ranges of temperatures, one just under the ground and three over the ground at heights ranging up to 2 meters high. It turns out that the temperature dropped by about 15°F with respect to where it would have been given the normal rate of warming. And the deepest part of the drop was delayed around 10 minutes, an expected thermal lag. I was able to show a graph.
Tomorrow's papers deal with largely theoretical aspects of the magnetic-wave-heating of the solar corona. There is still lots to learn and lots to discuss among astronomers from all over the world.
On to Easter Island.
A total solar eclipse image from Tianhuangping, China (outside Hangzhou at 900
m altitude) during the 22 July 2009 eclipse, merged with a SOHO Extreme-
ultraviolet Imaging Telescope (EIT) disk image in the helium 304 Ā emission line
and a Large-Angle Spectrometric Coronagraph (LASCO) image of the outer corona.
The corona was very sparse because of the exceedingly low phase of the sunspot
cycle, really a cycle in the solar magnetic field known as the solar-activity cycle.
Williams College Eclipse Expedition: Jay M. Pasachoff, Bryce A. Babcock, Katherind DuPré, Sara
Dwyer, Rachel Wagner-Kaiser, Yung Hsien Ng Tam, Huajie Cao, Paul Rosenthal, Jianjun Wang; EIT image courtesy
EIT Team, NASA's Goddard Space Flight Center; LASCO image courtesy of LASCO
Team, Naval Research Laboratory; compositing by Steele Hill, NASA's Goddard
Space Flight Center