Sailors and Astronomy

I never knew or even thought about before Copernicus, Ptolemy, and even Aristotle astronomy was shaped by mariners; although it does makes sense because they were never stationary so they had the best views of the night sky, and they were able to identify and changes. It was also interesting to read that historians had trouble discovering this due to the mariners ever writing anything down. Everything was learned by word of mouth or actual hands on experience in those sailing situations.