I don't know if this question is a good fit for here - it probably wants the non-existent "History of Astronomic Navigation SE", or maybe just "History SE" - but I'll start here:
As described in this article here by Dr Mario Livio: The Talmud (an 1500-2000 year-old Jewish book of laws and traditions) describes how a Rabbi anticipated hs ship getting lost, because “There is a star that appears every 70 years and induces navigation errors. I thought it might appear and cause us to go astray.”.
Various theories are put forward to the identity of this star - with the 70-year period suggesting Halley's comet, although another theory posits that it was a variable star (see article for details).
My question is one that the article doesn't seem to address: How could a comet or a variable star confuse sailors? Comets don't even look like stars, so as long as they don't cover up the Pole Star or any other important navigational bodies why should they confuse sailors?