Paraxial Ray Tracing Using Matrices, with a FRED Example of a Cassegrain Telescope

[@benm4823]

Hi Stephen, thanks for making and sharing optics videos. Your Zemax videos are really helpfull. A video that reviews Zemax from basic to setting up complex non sequential systems will be really valuable.

[@Ismailia007]

Amazing videos.
Could you also make another video detailing the Seidel sums for a glass plate (2 parallel surfaces, thickness t, and index n) in air?

[@mas13662002]

Can you show your steps for backward raytracing please.thanks