Everything you ever wanted to know about the planet Jupiter

Sean C · 05-04-20, 06:48 PM

Galileo discovered the four largest moons of Jupiter (Europa, Io, Callisto and Ganymede). He devised a method to determine one's longitude on Earth by timing the disappearance of these moons behind the planet.

Unfortunately, this was impossible to do on a moving ship and so was only really useful on land. But, apparently the method was used by Cassini and Jean Picard to produce a new map of France.

05-04-20, 06:48 PM	#11
Sean C Grey Wolf Join Date: Jun 2017 Location: Norfolk, VA Posts: 988 Downloads: 16 Uploads: 2	Galileo discovered the four largest moons of Jupiter (Europa, Io, Callisto and Ganymede). He devised a method to determine one's longitude on Earth by timing the disappearance of these moons behind the planet. Unfortunately, this was impossible to do on a moving ship and so was only really useful on land. But, apparently the method was used by Cassini and Jean Picard to produce a new map of France. __________________ If you have a question about celestial navigation ... ask me! Celestial Navigation Spreadsheet