Some women are known to have tetrachromacy. The ancient were well aware of such individual differences and would have utilized them for scientific ends. Near sighted people were their microscopes. They were each very aware of their senses because of the way they thought.

[en.wikipedia.org]

Measuring the angle between "yellow" and "blue" in each the rainbow and moon bow would have been very easy for a tetrachromatic. I think I could do it except my memory for color is poor. My range would probably exceed the actual measurement.

Now days the FED could just train honeybees to do it. ;)

This stuff should be easy enough.