This sentence has a number of ambiguities, many of which were not resolved in later posts.
1. What kind of very vivid images? Mental, artist representations (as suggested by subsequent posts), actual photographs? If well documented by photographs, why use an artist's representation, and why was the entire incident, which sounds very dramatic, forgotten?
2. Does this guy actually believe that the UFOs were extraterrestrial aliens, or some common mis-identification (Venus rising, etc.) or something else? UFO literally means unidentified, and it is never clear what the speaker was proposing.
It is a bit disturbing to hear that the speaker also appears to feel that 2% of the population are telepathic (you guys know that I mean you) and describes himself (?) as an astronomy and archaeologist both.
The Arkansas Sky Observatory appears to be a site for largely amateurs to use their own telescopes and some high end hobbyist telescopes and other equipment. Don't get me wrong- it looks really neat from the web site. But it is hardly an academic establishment and appears to allow its use by many people with a range of credentials.