Thanks for stopping by and I’m glad to hear that you liked this topic. Regarding refraction, studies start with Ptolemy, but it seems that around the year 1000 a certain Alhazen (Ibn al-Haytham) even wrote a book called “The Book of Optics”, which could be considered the first serious approach to the refraction of light. Refraction is a topic that has attracted scholars since ancient times. !HUG