What is a person who studies rainbows called?

"can anyone answer im looking to with no results"

The reason you're not getting any answers is that no one "studies rainbows". Rainbows have been essentially completely explained, and we know just about everything there is to know about them, so as you can imagine there's not a great deal of interest in studying them.

However, as always, for scientific terminology Latin is our friend. If there were such a thing as a scientist who studied rainbows, the term would be "iridologist." It sounds almost like a real science, doesn't it?

There's only one problem: the term is already in use for a pseudo-scientific medical practice (aka "quackery") in which the patterns and colors in the iris of the eye are used to pretend to "diagnose" medical conditions. So any putative rainbow-studiers would have to come up with another term, or be forced to constantly explain that they were from an entirely different pseudo-science.