"Every now and then, in ancient times, when conditions were right, one of these guys would look at Saturn and notice that it had associated elements."
While it is true that there are variations in visual acuity between individuals, the likelihood that an individual with extraordinary eyesight (think Chuck Yeager) would see the occasional (at best) phenomena as anything other than an aberration is, I believe, low. Even after this rare event had taken place, that person is then tasked with explaining to his contemporaneous that he can see thing that others cannot, no small undertaking.
"That didn't keep him from describing the rings as 'horns'."
Here is Galileo's description of his observation of the rings of Saturn:
"I have observed the highest planet [Saturn] to be tripled-bodied. This is to say that to my very great amazement Saturn was seen to me to be not a single star, but three together, which almost touch each other".
From: Historical background of Saturn's rings
http://www2.jpl.nasa.gov/saturn/back.htmlBTW, the ability to detect "red" with above average accuity gives you an edge in hunting game. That sort of thing makes you very, very valuable, and they'll believe you quite readily.
BTW, being familiar with the phenomenon, I will assure you I can find a red-head at distances virtually unheard of. (when given the choice) I purchase only red cars, and red is the only truly "bright" color.