David Levy is one of the great contemporary comet hunters. The co-discoverer of Shoemaker-Levy 9, which collided with Jupiter with spectacular results in 1994, he has found nineteen comets.
I met him while he was hunting comets in London, Ontario, in the 1970s. Then as now, he recognized that the only predictable thing about comets is their unpredictability. "Comets are like cats," he said. "They have tails and do precisely what they want."
The Quest for Comets, reissued in the wake of comet Hale-Bopp, expresses the excitement of a contemporary astronomer looking at his specialty with warmth and knowledge. Quoting Leslie Peltier, a well-known America astronomer, David says: "To hunt a speck of moving haze may seem a strange pursuit, but even though we fail the search is still rewarding, for in no better way can we come face to face, night after night, with such a wealth of riches as old Croesus never dreamed of."
The key phrase is "speck of moving haze". As anyone who has seen a comet knows, they are generally subtle objects, beautiful but barely noticeable even when pointed out. They are not terrifying. And yet the ancient view of comets was so different that it almost seems as if pre-modern comets were made of different stuff. Shakespeare wrote in Julius Caesar, "when beggars die there are no comets seen, The heavens themselves blaze forth the death of princes." The Bayeux Tapestry, showing Halley's Comet as a broad streak across the sky, proclaims "Nova stella, novus rex." Even Ptolemy attributed "heated and turbulent" dispositions in the "constitutions of men" to comets. All this for a fuzzy speck?
Of course, comets used to be easier to see. "Light pollution", the permanently luminous background glow created by modern cities, was almost unknown until modern times. Objects invisible in, say, Toronto or Vancouver in 1997, were clearly visible in Elizabethan-Jacobean England or ancient Greece. Today, the Milky Way viewed from a dark rural location can be a revelation. That said, comets were not any more spectacular than other celestial bodies; the drama associated with them comes not from their appearance or movement but from their novelty. Comets were stars not seen before, appearing in the sky briefly, sometimes bright, sometimes not, but, most decisively, new. They were seen in a different framework. As inexplicable intruders in a heaven that was believed to be perfect and unchangeable, comets were dreadful harbingers of disorder. Speaking of a great comet of 44 BCE, appearing around the death of Caesar, Plutarch wrote, "Among the divine portents there was also a great comet; it appeared very bright for seven days after the murder of Caesar." Daniel Defoe spoke of comets as presaging the plague.
Just recently, the Heaven's Gate sect held the pre-modern view in an overwrought form. They saw Hale-Bopp as a mystery concealing a spaceship.
With remarkable aplomb, exuberance, and style, David Levy moves from the history of comets to his personal history in comet-hunting. Sometimes his stories are profound, sometimes less so. Here is one story about him, his telescope, and two strangers:
"With Halley's comet far in the southern sky in spring 1986, I did get to go to Peru to lead a Halley's comet expedition. On the first night, I was scouting our observing area for the best place to watch-just me and Minerva, my 6-inch telescope. It was a remote site on the grounds of an Inca ruin.
"As I was concentrating on the comet, I didn't hear some faint distant footsteps until they were loud enough so that I could tell somebody was approaching. The steps got louder; there was a clinking of glass. There was conversation in a language I had never heard before, but it was clear that my uninvited visitors were somewhat soused. Not knowing what to do, I looked at the distant comet and then at Minerva. Hmmm, I thought, telescope as a weapons system. If they got threatening, maybe I could hit them over their heads with my telescope.
"As the men got closer-in the starlight, they seemed to be awfully big hombres-my fears were confirmed. There were two, they were drunk, and they were staring straight at me. For a minute, the three of us stood there. I looked at them, they looked at me, at my telescope, then at the sky. Then they pointed. `Hal-leee?' I offered them a turn at the eyepiece." 

James Morton is a lawyer practising with Steinberg Morton Frymer in Toronto. He teaches at Osgoode Hall Law School.