William R Wood wrote: "There is a huge difference in ratings between my 5" refractor and 10" reflector on the same night set up side by side. A decent rating of 5/10 with the refractor usually means a horrendous rating of 2-3/10 with the 10". How would two observers compare observations as sky assements would be different for each observer ? Ken Sikes -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.