Eclipse in a box

Not wanting to be bothered with 'special sunglasses' to view the eclipse today, we just used a shoebox as a pinhole camera to watch the shadow of the moon cross the sun's face. And it did give us a rather good view of the eclipse's progress, though we had to keep moving the shoebox constantly to make sure it caught the sun's rays.

The astronomers of the Madras Presidency, during the 19th century, were considerably better equipped. They had state-of-the-art equipment at their command, for the British knew that accurate astronomical observations would directly help in better navigation - and also for better understanding the geography of the subcontinent which was now under their control. As part of these observations, the astronomers would also study the solar eclipses. It was only the later half of the 1800s that these observations laid the foundation for solar physics, a hitherto unknown branch of science.

More specifically, it was the total eclipse of Augst 18, 1868 which set off the spark for the new science. In a display of scientific cooperation, the team from the Madras Observatory was joined by an addtional team of British astronomers, as well as a team of their French counterparts, to study that eclipse. Observing the event from different locations in and around Madras, the teams found their spectrometers displaying a bright yellow line, which could not be explained away as sodium. It was based on these observations that Pierre Janssen and Norman Lockyer deduced the existence of Helium, leading to both of them being jointly credited as having discovered that element - though it is almost forgotten that it was the Madras Observatory which set it up for them*.

Our observations from the shoebox did give us a lot of fun; no new elements were discovered in the process, however!

* Though Janssen made his readings at Guntur and Lockyer at Vijaydurg, all the arrangements for observing this eclipse - and subsequent ones - were made by the Madras Observatory, which was the leading, if not the only, astronomical observatory in India at that time.