moons of Jupiter, which can then be used to estimate time from that longitude.

IlluS Tra TIon By Gary ne Ill

This is why Greenwich Observatory in the U.K. and the U.S. Naval Observatory were funded by their respective admi-ralties. The British empire staked some money on this question, and while the astronomers won on dirty play, the audience vastly preferred John Harrison’s chronometers because you did not need to see the transits of the moons of Jupiter to know what time it was. Harrison’s chronometer just told you, any time you wanted to know. 4

Ever since, astronomers have lost
ground as “time lords.”
Time zones, made necessary by
transcontinental railroads, reduced
the number of necessary observatories
to nearly nothing. Previously, every re-
spectable city, with or without a univer-
sity, had somebody whose job it was to
figure out proper time. With time zones
and a telegraph, you could service all of
the United States from the Naval Obser-
vatory.