Fata Morgana in the Juan de Fuca Strait
epod.usra.edu
epod.usra.edu
My great-grandfather once saw a semi-mythical island settlement on the horizon in the area where he used to fish (he was a fisherman). There are many stories about that place. My great-grandfather understood what he saw though -- it was a mirage of a real settlement, on an island much farther out. Too far out to see normally, but conditions can sometimes show a mirage of it. And that's where the mythical place and the stories came from.
[1]https://turcanin.wordpress.com/2012/07/31/fata-morgana-the-m...
This link was the most helpful: https://www.atoptics.co.uk/fz139.htm