Old C80 f11.4

I recently aquired an old Celestron (80's or early 90's) 900mm, f11.4 refractor. I am really surprised at the very good optics and color correction of this scope, considering it cost about $100.00. It came with a mount I was interested in purchasing. I see very little color on bright stars or the moon. Color correction seems as good as many of the shorter focal legnth ED scopes out there. I would appreciate any commements on this scope or other long focus achromats with regard to color correction vs faster "ED" scopes.