>> If the instruments are significantly different they'll give >> different results.... Right, so it'll be you with your 14-inch or whatever at some medium-high power that you would always make these estimates with. Actually, seeing estimates won't vary as much as you think since the general blur you get with larger apertures is replaced by bulk image-motion at smaller apertures (and the small-aperture observers should include image-motion in the seeing estimate, which I think was discussed when went through this last time). \Brian -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.