Note that on their website promo for the Celestrons new DK 20" the company make's the claim that quote: "Celestron’s Dall-Kirkham design exceeds the off-axis performance of even the Ritchey-Chrétien design." I wonder how the folks at OGS and RCOS feel about that...
http://www.celestron.com/prod_pgs/tel/c20_index.htm
http://www.celestron.com/prod_pgs/tel/c20_index.htm
Scott
URL http://www.SPACEAHOLIC.com/
Preserving Space History for the Future