Large Telescopes And Why We Need Them

[CraigT82]

Stumbled across this lecture no youtube tonight... Great way to spend an hour - learning about how telescopes have evolved and their different designs.  I always knew that light was refracted when it passed through mediums at different velocities but I never knew why and there's a really simple analogy in this video that explained it to me!

https://www.youtube.com/watch?v=qk_8Jv2GO8g

[Sonicfishcake42]

Just watched this, great find! Thanks very much for sharing. 
 

[baggywrinkle]

Good link.

I have been lucky enough to see Caroline Crawford 'live' on two occassions. She gives some magic presentations.