Sometimes, Canon puts out a article that delves into techniques that are informative and pertain to many forum members. This is one of those. Some experienced solar photographers will find nothing new here, but for most of us, its a excellent article with lots of practical hints and how to information pertaining directly to Canon DSLR's.
"Historically Speaking Since the earliest days of photography, scientists worked at making a successful image of the corona during a total solar eclipse. The first correctly exposed photograph of the corona during a total solar eclipse was made on July 28, 1851 by daguerreotypist Johann Berkowski at the Royal Prussian Observatory at Königsberg (now Kaliningrad, in Russia). The exposure was 84 seconds during maximum eclipse. Numerous attempts were made earlier, but Berkowski’s image was the first correctly exposed image.
A cropped and enhanced version of the original Berkowski daguerreotype of 1851 clearly shows that not only did Johann Berkowski correctly expose his 84 second daguerreotype, he was the first to document the solar flares, known as prominences, emanating from the sun's surface. This daguerreotype became the benchmark for later photographic attempts ... "
http://www.learn.usa.canon.com/resources/articles/2017/solar-eclipse/photographic-exposure-solar-eclipse.shtml
"Historically Speaking Since the earliest days of photography, scientists worked at making a successful image of the corona during a total solar eclipse. The first correctly exposed photograph of the corona during a total solar eclipse was made on July 28, 1851 by daguerreotypist Johann Berkowski at the Royal Prussian Observatory at Königsberg (now Kaliningrad, in Russia). The exposure was 84 seconds during maximum eclipse. Numerous attempts were made earlier, but Berkowski’s image was the first correctly exposed image.
http://www.learn.usa.canon.com/resources/articles/2017/solar-eclipse/photographic-exposure-solar-eclipse.shtml