[RonF]

I visited the Yerkes Observatory 2 years ago, and checked out the 40" (the largest refractor in the world). It was built in 1897 and is still used for research. One thing they use it for is to take star pictures. These are compared to pictures of the same stars taken up to over 100 years ago so as to measure proper motions. At the time the initial pictures were taken this was the world's largest telescope, so you can make precise measurements of proper motions possible with no other telescope in the world.

I was at a Scout meeting at George Williams College next door, but skipped out to take a tour of the facility (9:30, 10:30, and 11:30 Saturday mornings), on the justification that I'm an Astronomy MB counselor, plus I just wanted to.

[bedolido]

They're considering a replacement for the Hubble (named after another great astronomer). This new Hubble replacement will be slightly larger with the mirror going up in several pieces. This new mirror will allow more light in thus bring objects from deep space even closer.