Celatone

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.

In 2013, Matthew Dockrey created a replica celatone, using notes from a version created by Samuel Parlour.

From April 2014 to January 2015, Dockrey's celatone was on display in the Royal Observatory, Greenwich in east London.

Using of celatone.
Celatone by Matthew Dockrey. Museum at the Royal Observatory, Greenwich, UK.