Sky & Telescope December 1985 [antikvár]

Sir Dames South and the Cauchoix ObjectiveNicholas Der Bagdasarian, West Hartford, ConnecticutAS ASTRONOMERS from PalomarL Mountain to Stellafane know, the obsession to construct bigger and better telescopes has been a central theme in the recent history of astronomy. In the early 19th century, an effort to build the world's largest refractor engrossed an astronomer now consigned to oblivion. Sir James South.South was born in London in 1785. As a young man he acquired a prominent reputation as a surgeon; one contemporary has commented that he had "a keen eye, a steady hand, great power of bearing fatigue and want of sleep . . . and boundless enthusiasm." These were qualities any astronomer might envy. However, though the night sky had long been his hobby, what ultimately enabled South to leave the operating table for the stars was his marriage in 1816 to a rich heiress. Henceforth he devoted his time exclusively to astronomical pursuits, beginning with the construction of a home observatory equipped with several telescopes.At the turn of the 18th century, astronomers were caught up in a race to discover and map binary stars. William Herschel inaugurated this interest in 1799, with the publication of a list of 269 pairs. South, armed with his collection of instruments, was determined not only to improve upon Herschel's observations, but also to make his own discoveries. In 1821 he joined forces with John Herschel, William's son. After working together for several years, they published a catalogue of 380 double stars that remained a standard work for years. Finding the polluted atmosphere of London unsuited to his work, however, South moved temporarily to France, where he conducted measurements on an additional 458 double stars, of which 160 were newly discovered.South's contributions were recognized by his peers, who elected him president of the Astronomical Society in 1829, and the royal charter granted to that organization in 1831 was made out in his name. When he contemplated permanently moving his telescopes to France, the British government bribed him into staying by bestowing knighthood upon him. Not long afterward South was granted an annual government pension of L300 to continue his observations there. Consequently he purchased a site southwest of central London at Camp-den Hill, Kensington, to construct an observatory, for which he wanted to obtain a truly first-rate equatorial refractor.Sir James South. Photos from History of the Royal Astronomical Society, 1820-1920.Swiss Pierre Guinand and Frenchman Robert Aglae Cauchoix had recently introduced technological innovations to the art of lens making, permitting the manufacture of objectives of a size hitherto unknown. Cauchoix had succeeded in making the world's largest lens, an 11%-inch objective, which was mounted on a telescope at the Royal Observatory in Paris. This particular telescope had become especially popular with the French nobility, who used it for moon-gazing parties.South's interest in the lens was kindled, according to one account, by the astronomer E. J. Cooper, who in 1829 had contracted to purchase it from Cauchoix. On his return from Paris, Cooper called upon South and boasted about the excellent optical properties of Cauchoix's creation. This so aroused the envy of South that, upon Cooper's departure, he immediately sped off to Paris, paid Cauchoix L1,200, and brought the lens back to Kensington the next day, narrowly avoiding the frantic attempts of French government astronomers to stop him at the border. The English government facilitated South's coup by allowing the glass into the country dutyfree. Upon hearing the news, the London Times gloated that the French "can now only look through an open tube."Having obtained the lens, South now turned to his good friend Edward Trough-ton to provide an equatorial mount for the glass and a dome to house the telescope. The lives of these two men had run parallel for many years. Both had served onthe Council of the Royal Astronomical Society and both had been awarded the society's Copley medal. They saw each other nearly every day, and it was only natural that South should commission his friend to do the work. Troughton was, after all, the most famous instrument maker of his time, having fashioned equipment for observatories throughout the world.Troughton, however, had his drawbacks, being somewhat eccentric and prone to speaking his mind. He was also 76 years old in 1829 and not in the best of health, having become reclusive and rather deaf. Most of his time was spent in the parlor of his home on Fleet Street where, dressed in dirty clothes and wig, he hobbled about with his large ear trumpet.Ominously, as work on the mount and the dome progressed, several of South's friends pointed out that neither was being constructed with much regard for the rudimentary principles of engineering. Sir James shrugged off such warnings with the complacent statement that all was well because "it is designed by Troughton." However, as time went on even South became apprehensive, interfering in the construction and urging the use of different materials.