Members Evening – 23rd November 2006

Gilbert Satterthwaite gave the first talk of the evening on “Airy’s Altazimuth Telescope“. This instrument was installed at Greenwich by Airy, and was used very successfully to record the Moon’s position with greater accuracy than had previously been possible. Considerable attention had been given to its design and placement. It weighed about 2000 pounds, quite a substantial amount for a telescope of modest size, and this contributed to its success. Sadly it was replaced at the end of the 19th century by a larger but less well designed (and less successful) instrument, and Airy’s telescope is now in storage in the Science Museum. There is some hope that it may be put back on display sometime.
Tony Buick then gave a short talk, somewhat frustrated by technology, about his recent attempts to capture images of man-made satellites.
Greg Smye-Rumsby brought the evening to a close with a short talk about “Planetary Occultations“. These events are so rare that there are no recorded observations, but Greg put his artistic skills and astronomer’s knowledge into constructing images of some of the possible events in the next few thousand years, ensuring that relative sizes, brightness and illumination of the planets was as accurate as possible. He also mentioned that the accuracy of any predictions is highly dependant on the correctness of the data from which they’re derived and the accuracy of the calculations. However, as most of the events he listed were over a century in the future, acccuracte predictions are only of accademic interest to most of us.