Astronomy today has acquired an important position among the sciences, thanks to the pioneering effort of early astronomers. The year 2009 reminds us of Galileo who demonstrated how the use of a telescope can enhance our view of the cosmos. Later, Newton himself devised a new form of telescope, which pioneered new designs for telescopes. The Newtonian telescope used a mirror instead of a lens and that approach is followed even today.

But instruments apart, in the last analysis, it is the enthusiasm of observers to use them, sometimes under adverse conditions, that has been an important factor in the progress of astronomy. Some events, such as eclipses occur at specific times and have to be observed only at those times.

Here is the story of a French astronomer who visited India in order to observe the transit of Venus. A transit occurs when the planet crosses the solar disc as seen from the earth. The planetary disc is too small to cover the sun as in a solar eclipse. Yet the phenomenon is worth observing and its precise measurements can give us detailed information about the geometry of our solar system.

Guillaume Le Gentil was the astronomer who came to India from Paris in 1761 and stayed here for several years. He did important astronomical work on oceans and also to determine the longitude of Pondicherry. He published the results in Paris in 1779 in his research work, Voyages dans les Mers de l’Inde.

Le Gentil, however, encountered several misfortunes in his ventures. He was initially deputed by the King of France on the recommendation of the Academie Royale des Sciences to observe the transit of Venus across the solar disc, which was to be visible in Pondicherry in 1761. He left France on this duty, but because of the seven-year war between England and his country, he had to take several detours to avoid the war zones. So when he reached Pondicherry on June 6, 1761, the transit had already taken place. Like time and tide, astronomical events do not wait for anyone.

Nevertheless, Le Gentil decided to remain in India to observe another transit due eight years later on June 3, 1769. However, his patience was not to be rewarded, since when the prescribed date came, the sky was overcast and no observations could be made. (If it was any consolation, the British astronomers deputed by the Royal Society were similarly thwarted at Madras in their rival attempt.)

When Le Gentil sailed back to France, he was twice shipwrecked en route and arrived much later than expected. He arrived in Paris after 11 years of absence only to discover that he had been declared ‘legally dead’ and his property given away to his relatives. However, this sad saga has a happy ending: for Le Gentil eventually got married and lived happily ever after. But his misadventures give us an indication of how persistent some of these astronomers were in their attempts to add to our storehouse of knowledge on the heavens.

The frustrations of a washed out observation can befall an amateur as well as a professional. I recall going with a small group to Gujarat to observe the 1999 total solar eclipse. Those were the days of the monsoon and we were prepared for disappointment. We selected a secluded spot and waited for the predicted moment. As the moment came closer, we looked anxiously at the cloudy sky. Suddenly, as if on order, the clouds parted and we were rewarded with a view of the partially eclipsed sun. The patch of the sky containing the sun stayed clear well past the moment of totality. As we left the spot thanking our luck, we came across another group. Only half a kilometre away, they too had waited, but the clouds never parted.

The modern day astro-nomer may travel in a jet plane and make a dash across continents in a few hours to observe celestial objects on his telescope. However, he too cannot prevent his observation from being blanked out by a cloudy sky! A space telescope such as the Hubble Space Telescope is immune to the vagaries of the atmosphere, for it flies above it.

But we are fast approaching the automated remote control culture. Many telescopes these days positively discourage astronomers from being present at the observing time. Technicians, who really understand the complex machinery of a telescope, perform the task for them. The astronomer, on whose behalf a technician is observing, has to provide in detail the full protocol of what is to be observed. In the remote control mode, the telescope is run by computer commands issued by the observer, sitting not in the telescope building, but in his office thousands of kilometres from the telescope. This saves the Le Gentils all the misadventures of travelling!