Hi, I'm trying to get a feel for Antoniadi seeing scale and the Pickering scale for apetures above 250mm. I understand that larger apetures scopes show less variation in the seeing disk than let's say a 5 1/4 inch refractor or a 6 inch DOB. Specifically, I'm interested in the poor end of the Antoniadi scale. Since the seeing disk is much smaller in a larger apeture scope, the variation in the seeing disk is supposedly much lower in poor seeing, than the 3 or 4 arcsecs that I might see in a small refractor or binoculars. Having almost no experience at those apetures except for the occasional peak through the Grimm scope, I would looking for some experience based statements from those who do. - Kurt ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ