A total solar eclipse is a remarkable alignment of our sun, Earth, and moon, as the latter casts a perfect shadow over the former.
If you are in the narrow path of the moon’s shadow, you are enveloped in darkness at the moment of totality. Stars and planets appear in the sky and the entire atmosphere changes. This immersion in a total solar eclipse is unforgettable.
Like 21-year-old Australian Miriam Chisholm reported in 1922,
I looked up from the telescope just before totality and thought I saw the Corona, a pale rim around the sun […] and then the light went out and we saw it in all its glory.
Historically, total solar eclipses have been a unique opportunity to conduct scientific research on our sun, the closest star. Using special instruments called spectroscopes, it was possible to decipher the chemical composition of the gases emitted by the sun, but only during a total solar eclipse.
As I write in my recently co-authored book Eclipse fighters, perhaps the most famous eclipse experiment was the proof of Albert Einstein’s general theory of relativity. In the early 20th century, this theory could only be tested during the minutes of totality, which required a clear sky around the obscured sun to photograph the stars.
Women in the field
Accounts of well-known historical discoveries in astronomy may give the impression that this work was done only by men. But in the late 19th and early 20th centuries, women in Australia were already taking part in astronomy female “computers” and amateur astronomers. They were heavily involved in scientific expeditions to view total solar eclipses, but it wasn’t easy.
Living conditions were rough, in tents with poor facilities, open to the weather, and little or no privacy. The months it took to travel on eclipse expeditions meant giving up family responsibilities, one of the reasons it was unusual to find women in the field. When women participated, they were usually the wives and daughters of male astronomers.
The first Australian woman whose sightings of a total solar eclipse were officially reported was Annie Louisa Virginia Dodwell. She had a Bachelor of Science from the University of Adelaide and acquired astronomical knowledge working with her husband George Dodwell, the South Australian government astronomer.
Together they organized the Adelaide Observatory Expedition to Bruny Island in Tasmania for the total solar eclipse of 1910. The party arrived by ship and for a month they camped in tents in almost constant rain to prepare. The eclipse day was cloudy, but Annie successfully recorded the temperature change, the only valuable science achieved.
In the following years she presented talks about astronomypublished poems and participated in the inaugural meeting of the International Astronomical Union at the Vatican Observatory in 1922. She arranged the logistics for her husband’s total solar eclipse expedition later that year, during which she his observations transcribed to the newspapers.
Read more: A century ago, Australia was ground zero for eclipse watchers — and helped prove Einstein right
Seasoned eclipse hunters in the 1920s
In 1922, an international team of astronomers, led by William Campbell, director of Lick Observatory, and assisted by the Australian Navy, traveled to a remote location in Western Australia to test Einstein’s general theory of relativity during the September 21 total solar eclipse. to confirm.
Five women took part in this expedition: Elizabeth Campbell, Jean Chant with her daughter Elizabeth, Eleanor Adams and Mary Acworth Evershed.
Though they were the wives and daughters of respective male astronomers, each woman was a seasoned eclipse observer in her own right. They knew how to operate and use technical equipment and contributed substantially to the reporting of the scientific work.
Elizabeth Campbell organized supplies and operated spectroscopic and photographic telescope equipment during the eclipse. Eleanor Adams worked with her husband on the large 12-meter eclipse camera. Jean Chant observed the shadow bands and changing brightness of the sky, and Elizabeth Chant operated a prism that polarized light.
Mary Acworth Evershed was an established expert in solar physics and worked with her husband, director of the Kodaikanal solar observatory in India. She photographed the spectra of the sun’s corona. In 1896, upon returning to England, she published a pocket-sized Easy Guide to the Southern Stars containing star charts of the constellations visible from the Southern Hemisphere.
A long drive across the country
On the other side of the continent, 21-year-old Miriam Chisholm and her school friend Frida Tindal organized a very different eclipse expedition. Chisholm’s father, Frank, drove them more than 600 miles from Goulburn to southern Queensland.
They lost four days when their car was stuck in the mud and almost fell short of totality. Fortunately, thanks to excellent timekeeping and navigation, they had a successful eclipse. They drew the sun’s corona, measured its temperature, observed how animals and birds became silent, and timed the shadow bands. Their report is descriptive, inspiring and filled with detailed observations. It’s still a handy guide to getting the most out of a total solar eclipse.
On April 20, 2023, a total solar eclipse will be visible from Exmouth in Western Australia. This is Australia’s first total solar eclipse since 2012, when thousands of people moved to northern Queensland. I was there and for two minutes and five seconds of totality, I experienced a beautiful “diamond ring” effect as the moon completely covered the sun, revealing its misty corona.
There are four more total solar eclipses in the next 17 years. Following in the footsteps of early 20th century eclipse hunters, large numbers of Australians will soon be able to share a total solar eclipse that they will cherish, record and retell for a lifetime.