Complex sentence: Nonius is a device, named in honour to its Portuguese author and inventor Pedro Nunes (Latin: Petrus Nonius), created in 1542 as a system for taking fine measurements on the astrolabe.
Split into simpler sentences: Nonius is a device named in honour of its Portuguese author and inventor Pedro Nunes (Latin: Petrus Nonius). The nonius was created in 1542 as a system for taking fine measurements on the astrolabe.