It required two regiments of Wallenstein’s men and two of Count Tilly’s to carry up the hillside the tube that arrived the next morning, this very instrument, the astronomer told Leibniz, patting the telescope, “two hundred and twenty-five feet long, per my specifications, and with the power to magnify objects that many times, a tube far longer and far more powerful than any of its predecessors.” “Who knows,” he had mused as the Sun went down, “how many stars we shall see tonight,” and his son had replied: “Who knows?” But by the time the Sun came up again they had catalogued 9,137 stars—not a single star more than they’d seen through the previous tube. Through two tubes of vastly different lengths the sky looked exactly the same. “The star catalogue was complete,” the astronomer told Leibniz. He added: “And how gratifying, how wonderful, how very providential, I thought, to complete my catalogue in my son’s presence—the very opposite of my father never completing his box in mine.” In case he had missed something up there, the astronomer did not stop in the weeks and months that followed to peer at the sky through his tube. But he had missed nothing; now and then he might see some celestial phenomenon he had not observed before, the tail, say, of a new comet, or the rings of Mars, which he was the first (“so I thought!”) to discover, as well as the rings (“so I thought!”) of Venus, but never again a new star, nor even a nebulosity that might be resolved into one. He felt less and less compelled to peer into his tube, until one day he ceased peering into it at all. Thereafter he and his son lived together in silence, just as they had when the boy was little, but it was now a different silence, a richer, warmer silence, actually an infinitely rich warm silence, there are two kinds of silence, this, the astronomer thought, was the other one. At Lützen, meanwhile, the King of Sweden was slain by a shot to the temple, Germany was saved, the war turned decisively in Ferdinand’s favor. Then years passed, and then decades, the astronomer became an old man and then a very old man, first a little bit bent over and then bent over a lot. He was one of those old men who was bent but serene, content with how he’d lived his life and what he had done in it.

“Until one night…”