He repeated: “His son in particular.”

In exchange the astronomer would be granted, first, an annual salary of so many thalers; second, stewardship of the Imperial Observatory, including access to the Castle Workshop, Castle Library, and Castle Laboratory, and carte blanche use, “within reason,” of the treasury for the making of his tubes, a “carte blanche” and a “within reason” that obviously—as the astronomer was later to realize—each annulled the other, for if “carte blanche” meant anything at all, “within reason” obviously meant nothing at all, and vice versa, “within reason” meaning something meant “carte blanche” meant nothing, not to mention that if he was indeed bound by reason, who knew what reason meant, if it meant by his own reason or by the Court Chamberlain’s reason or by some kind of shared reason, if such a thing existed, that is, perhaps his rights to the treasury extended only so far as the boundary set by common sense, a probably purposeful ambiguity that would intensify the Court Chamberlain’s power over him, with finally dire consequences; and third, he was granted for his living quarters a stately residence no less impressive than the Viennese mansion in which he’d been born. It was perched high on Hradčany Hill not far from the Castle, just beside an old Benedictine monastery whose bronze bells were pealing merrily as the astronomer pulled up in his carriage.

THAT DAY, THE DAY AFTER, and the day after that, the astronomer oversaw the construction of the first telescope, a brass tube thirteen inches long fashioned for him by a crew of expert metallurgists in the Imperial Forge and fitted at both ends with a lens of fine Murano glass purchased with imperial funds and shaped to the astronomer’s strict specifications by a master lens-grinder from Nuremberg along with his Augsburger apprentice, and which magnified objects two times. “In other words,” said the astronomer, “a magnifying power of two. You’ll want to write that down, Herr Leibniz, for the numbers will prove dreadfully significant in what is to come. Two, a magnifying power of two, and a length of thirteen inches.”

On the night of his third day as Imperial Astronomer he began cataloguing the stars. That night, the night after, and the night after that, he trained his astral tube at the celestial meridian. When a star crossed it he gave a shout, an assistant wielding a quadrant called out the altitude, another watching a clock called out the time, a third wrote down these two spatiotemporal coordinates in a ledger, which a fourth compared to the corresponding entry, if one existed, in the famous catalogues of Piccolomini, Tycho, and Bayer. Toward dawn on the first night, throughout which the monks in the monastery kept their bells ringing continually as if in anticipation of his feat, the astronomer surpassed the 919 stars enumerated by Piccolomini.