The entire FOV is without sweet spot with any eyepiece used including 100* ones and show no vignetting with the B15 or the Lunt BF1200 in single or DS mode! My single tilt etalon Lunt 60's sweet spot is about 80%. Also in DS the proms show equal detail as single at 115X which is the highest power usable today. So far both etalons are best with no tilt which the manual says is optimal. The Unistar-AP tripod the scopes on handles being used in DS or single without re-balancing though it's easy to do so. About the only negative so far is the UV hit I'm going to take using it. David
Edited by dscarpa, 14 June 2019 - 02:42 PM.