Message #124593

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                                       Let the global astronomy celebrations begin






Jan. 5, 2009

The International Year of Astronomy marks the 400th anniversary of the first use of an astronomical telescope by Galileo Galilei. As the 2009 celebrations kick off, Edwin Cartlidge explains how one of Galileo’s telescopes is being rebuilt by researchers in Italy, while Michael Banks looks at some of the events taking place this year


StargazingOf the many achievements of Galileo Galilei, among the most famous is a series of astronomical observations that he started in 1609 and announced in March 1610 in a publication entitled Sidereus Nuncius (“Starry Messenger”). These included radical new views of the Moon and the stars, as well as the discovery of four satellites orbiting Jupiter. By removing a major doubt about the heliocentric model — namely that the Earth appeared at the centre of things because only it had a satellite — the observation of the Jovian moons led to a new view of the universe and in the process brought Galileo considerable fame.

What had made these observations possible was the telescope. Invented in the Netherlands in 1608 (although there have been claims that it was first built a few years earlier), the telescope was initially seen as a useful new aid to warfare. However, once news of the device spread south, Galileo was able to use his considerable skills as an instrument maker to multiply the magnifying power of the basic spyglass so that he could use it as an astronomical tool.

Now, staff at the Institute and Museum of the History of Science in Florence, Italy, together with the Arcetri Observatory, also in Florence, have built a replica of one of Galileo’s telescopes and are using it to generate the images that, to the best of their estimations, Galileo himself would have seen. The aim, explains museum curator Giorgio Strano, is to understand exactly what Galileo observed and how he made his observations. “We are trying to distinguish precisely between what Galileo was potentially able to see ‘objectively’ with the telescope and what was, instead, the product of physiological, psychological and cultural factors,” he says.