gotta run...enjoyed it

I meant to ask you yesterday. What do you teach?

Good luck! Mine is in a STEM field. Getting through a defense isn't something I'd care to repeat.

I always enjoyed my history classes, however I no longer trust anything I was taught. Can you recommend a book on American History that isn't propaganda? Or perhaps some historians that can be trusted to present the facts?

Thanks. I'll look for that series. If you ever need help with an optical design, let me know.

No. Optics is the study of the interaction of light with matter. A rifle telescope or a the front end of a digital camera would be examples optical designs.

rifle scope

@Someguy That's pretty cool. Can you add the reflected ray at the second surface?

@Someguy they're there whether you want them or not. You don't really need to trace them unless you're doing stray light analysis. You do need to keep track of the loss you get at each surface, though.