Dave Candela said:
I own a 15" reflecror. I'm thinking about buying a 20" I live in a suburb of Chicago. Average skys. Is it worth the money to get 5 more inches of apperature, or is a 15" close to a 20 in the views you get. I've never looked through a 20.
I’ve used the C-14 and 20-inch F/8 RC Cass at Kopernik Obs (www.kopernik.org) since 1993. I also own an Obsession 20 and have used it at the same location. I’ve used the Obsession 20 at star parties featuring scopes up to a 36-inch. At least for me there is a noticeable difference between a 15 and a 20 inch. I personally would have bought something bigger than the Obsession 20, but alas, it’s the biggest scope I can fit thru the doors of my house.
George N