I thought it was fascinating. To me it is plausible that a lot of things have been invented more than once, so why not an ancient Greek navigational device? Our history has been pretty chaotic and violent -- there is probably a lot of knowledge that has been discovered and lost and rediscovered centuries later. If any ancient person could have had an understanding of the motion of the planets approaching that of Copernicus, it would have to have been some ancient Greek. The ancient people did seem to be able to navigate better than one might think -- maybe they knew more than we give them credit for.
Imagine what we could have learned if the library at Alexanderia hadn't burned down.