Abstract
Astronomy won't make you blind, according to Thomas Hockey, but there were and are sightless stargazers, not counting the character in the movie Contact.
First things first: it is a myth that astronomers blind themselves by observing the Sun. Galileo Galilei did not invent the astronomical telescope and then proceed to blind himself with one. As early as France's William of Saint-Cloud (c. 1290) astronomers knew that staring at the Sun was ill-advised and avoided it. Galileo observed the Sun near sunrise and sunset or by projection. More than two decades later he became blind as many septuagenarians do, for reasons unrelated to their profession. Thomas Harriot, Galileo's contemporary and a co-discoverer of sunspots, once observed until his eyesight was incapacitated for several hours – but he recovered and did not repeat the mistake. Even Isaac Newton temporarily blinded himself, staring at the reflection of the Sun when he was a twentysomething, from which we infer that young people in 17th-century England had limited access to recreational drugs. But permanent Sun-induced blindness? No, it did not happen.
But some notable astronomers were blind. Abbot Richard of Wallingford (c. 1291 – c. 1335) wrote astronomical works and designed astronomical instruments; he was blind in one eye. He also suffered from leprosy, so blindness seems among Richard's lesser problems. It was a stroke that left Scotland's James Gregory (1638–1675; you will remember the Gregorian telescope) blind. However, he died days later, so his blindness interfered little with his occupation. None other than the aged Giovanni Domenico Cassini (1625–1712) became blind, but only after he had retired and his son had taken over from him as director of the Paris Observatory. Similarly, Thomas Maclear (1794–1879), director of the Royal Observatory at the Cape of Good Hope, was blind only in retirement.
Far-sighted ideas
Perhaps the most famous professionally active, blind or almost-blind astronomer is Dominique-Francois Arago (1786–1853), director until his death of the Paris Observatory, a powerful role in 19th-century astronomy. However, his blindness came toward the end of his career, when his role was more that of a science lobbyist in the government. Arago was also a prominent advocate of the abolition of slavery. Both ideas were far-sighted, but furthering them did not require sight. Nicholas Mayall, director of the United States' Kitt Peak National Observatory, was colour-blind. Does that count? Probably not; it is a congenital condition and, while colour is an important characteristic of stars, it can be assessed from a spectrum. Nevertheless, being an observatory director (empirically, at least) appears to be hard on the eyes.
But I do not want to trivialize the affliction that is blindness. The aging William Campbell (1862–1938), one-time director of Lick Observatory and president of the University of California, became blind in one eye. Imminent failure of the other, as well as additional health problems, drove him to suicide in his 70th year. On the other hand, the Swiss celestial mechanist Leonhard Euler (1707–1783) was astronomy's Beethoven. He produced nearly half of his life's work while almost totally blind; he had an amazing memory. Still, many would classify him as a mathematician rather than an astronomer.
Dictation
The blind Russian Nikolai Lobachevsky (1792–1856), famous for Einstein's use of his non-Euclidian geometry, also comes in this category. For Lobachevsky, unusually, we know exactly the cause of his blindness: cataracts. He dictated his last work to a scribe, as did the cosmographic poet John Milton, when blind. Considering his subject matter, Lobachevsky must have had a scribe particularly adept at mathematics. And, among observational astronomers, there was Italy's Geminiano Montanari (1633–1687). He was the first astronomer to document the variability of Algol, the “Demon Star”. He then lost his eyesight.
To me, the most poignant tale of an astronomer who lost his sight is that of American Edwin Frost (1866–1935). He too was an observatory director – this time Yerkes. Frost had led expeditions of Yerkes astronomers to observe total eclipses of the Sun, at that time still a vital means of learning about the solar atmosphere. These expeditions had a poor track record and were often clouded out, as happened for the August 1932 eclipse. Indeed, clouds hid the Sun for most astronomers stationed along that New England eclipse path – except for one, the now retired Frost. But Frost never saw the eclipse. While at Yerkes he had become blind. He could walk from his house to the observatory only by following hand-level wire laid out specifically for him. As Donald Osterbrock tells the eclipse story in his 1997 book Yerkes Observatory: “Frost … accompanied his wife on a visit to their son, who lived in the outskirts of Portland, Maine … There they enjoyed perfectly clear skies, and the old director's grandchildren described the entire ninety-two seconds of totality to him.”
