I read that he didn't even use the stars much, one of the two main ways of navigating; he was a 'dead reckoning' man, as noted by Dude, and from his ship logs, sounds that way.

His birthday is Halloween, another fun fact.

thanks also to Dude re: 'quadrant', gotta look that up, sounds interesting. Yeah, the dead reckoning sounds like it might account for Columbus coming up a tad short of China/India but still thinking he was there!

thanks all!

https://twitter.com/asimom, https://contributingfactor.wordpress.com