The Astronomical Society of South Africa is hosting their biannual symposium in a few weeks at SAAO’s headquarters in Cape Town. The symposium lasts a few days, and features a mix of professional and amateur astronomers speaking on a wide variety of topics. I enjoy these symposia a great deal, as much for the people I get to meet as for the content of the talks, but one disappointment for me as a speaker is that it is not very open to the public. It costs a few hundred rand to register, and you feel compelled to attend all three days that you’ve paid for. I would certainly like to speak to the wider audience that a free, completely open event could attract.
Astronomer Ian Glass will talk about Nicolas Louis de La Caille (1713 –1762), the first important scientist to visit the Cape.
As a youngster Caille studied theology to please his father, but his real interest lay in astronomy. He was a member of the Royal Academy of Sciences in Paris, a textbook writer and an able propagandist for Newton’s theories. At the age of 39, he came to the Cape and built an observatory close to Rogge Bay, near the present-day Strand and Heerengracht streets. From this, he surveyed the southern sky through a telescope – the first systematic survey made in either hemisphere. He named fourteen new constellations after the scientific instruments of the time, except for one, Mensa or Table Mountain.
Other scientists in France had just found that the earth is not round, but is flattened towards the North Pole. La Caille decided to measure its shape in the south by means of astronomical observations and a ground-based survey from Cape Town to Piketberg. He was astonished to find that the planet seemed to be slightly pear-shaped! It was not until about 90 years later that Thomas Maclear could confirm the suspicion, first voiced by George Everest (of Mount Everest fame), that the instruments had been affected by the gravitational attraction of nearby mountains.
La Caille kept a most interesting Journal of his stay at the Cape containing, besides scientific notes, many comments on the colonists, the natural surroundings and other matters. His writing was precise and avoided the sensationalism of earlier visitors.