Celatone
Navigational aid reliant on tracking Jupiter's moons in the sky
From Wikipedia, the free encyclopedia
The celatone was a device invented by Galileo Galilei to observe Jupiter's moons with the purpose of finding longitude on Earth. It took the form of a piece of headgear with a telescope taking the place of an eyehole.
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Modern versions
In 2013, Matthew Dockrey created a replica celatone, using notes from a version created by Samuel Parlour.[1] From April 2014 to January 2015, Dockrey's celatone was on display in the Royal Observatory, Greenwich in east London.[1]
