On the night of March 24, 1993, astronomer David Levy was scanning the skies with his stargazing pals, Carolyn and Eugene M. Shoemaker. They photographed what appeared to be a train of 21 icy fragments stretching over 700,000 miles of space (three times the distance between the Earth and the Moon).
Further analysis revealed these were the fragments of a comet literally torn apart by Jupiter's gravity.
We now know it as Comet Shoemaker-Levy-9. Over a year later, in July 1994, Levy was on hand with countless other astronomers around the world to watch his comet collide with the gas giant.
This was neither the first, nor the last, notable discovery by Levy, who first became interested in the stars as a young boy. His degrees, ironically, are in English literature, but it is for astronomy that he is best known — despite the fact that a prominent member of Royal Astronomical Society of Canada (RASC) once declared, in 1968, that "Levy will never amount to anything."
At last count, Levy has discovered 22 comets, and written 34 books and innumerable popular articles. Now he has donated digitized editions (digitized by his daughter, Nanette) of his personal observational logbooks to the RASC, starting in 1959 when, at age 11, he spotted the Big Dipper and observed his first partial solar eclipse. Now anyone can sign up and gain access to Levy's 16,000+ observing sessions, which include occasional sketches and photographs.
As an extra treat, you can peruse a wonderful essay (PDF) by the RASC archivist, R.A. Rosenfeld, on the long tradition of astronomers keeping such logbooks; he considers it "a literary genre with a history and conventions, and intriguingly and paradoxically are personal documents reflecting the research style of those who created them."
There is some controversy over just how early one can date this tradition of record-keeping, but there is evidence that certain marks and engravings on bones — dating back to 32,000 B.P. and 13,000 B.P. — could have been graphical records of phases of the moon. As yet, it is speculation, but an intriguing hypothesis, nonetheless.
For actual surviving records, Rosenfeld says, one must go back to the Babylonian Astronomical Diaries, carved in cuneiform on clay tablets, the oldest of which date back to 652 B.C. It's possible that ancient Egyptians and pre-Hellenic Greeks may also have kept observational records, based on secondary evidence found in the writings of Hipparchus and Ptolemy.
By the late 11th century — the so-called "Dark Ages," which Rosenfeld argues is a misnomer — recorded astronomical observations were far more common. By the time Galileo, Christian Huygens and William and Caroline Herschel were making their pioneering observations, such record-keeping was commonplace — and quite similar to the logbooks kept by modern astronomers, like Levy.
As Rosenfeld says: "In the still of the night, under the dome of heaven, it is possible to experience a quiet quickening in the marrow, knowing that such archetypal watchers of the sky observed and recorded in a fashion not altogether foreign to the conteporary amateur experience." Now we can add Levy's logbooks to the archives of astronomy history, so that one day, hundreds of years from now, another young boy gazing up at the night sky will carry on Levy's tradition.
Image: Comet P/Shoemaker-Levy 9 as taken with the Wide-Field/Planetary Camera on the Hubble Space Telescope (17 May 1994). Credit: H.A. Weaver, T. E. Smith (Space Telescope Science Institute), NASA