开云体育

Here time line
The astrolabe is an intricate astronomical instrument invented in Ancient Greece around 150 BC. It enabled measurements of celestial objects like stars and planets, told time, determined latitude and longitude, and performed astronomical calculations. The astrolabe was a revolutionary navigation aid that utilized star positions to find one's position at sea. It remained the most widely used scientific instrument until the late 17th century1. The history of the astrolabe begins in Alexandria and moves to the Byzantine Empire and the Islamic world, where it flourished from India to Muslim Spain.?

?? ? Dead Reckoning ?? ?

Dead reckoning was noted in the 1500's this does work for very low tech Longitude by using charts and compass. Basically give apx miles travel in a given direction. Then with know ladatude can give a close location. There variable that could 100s of miles off



The sextant's origins trace back to ancient times, but its modern iteration, commonly referred to as Hadley's Sextant, was created by John Hadley and Thomas Godfrey in 1730. The sextant is a navigation instrument used to measure the angular distance between two visible objects. The earliest known sextant was created by John Bird in 1757



John Harrison's invention of a chronometer that could keep time at sea with sufficient accuracy to be practical for determining longitude was recognized in 1773 as first enabling determination of longitude at sea. Later methods used the telegraph and then radio to synchronize clocks