Quote:Thanks Silvio,I would ask, when you get the time could you check this to help clear up some confusion.You have stated above and Oberwerk lists on their website that the focal length is 520mm for f/6.5. However, the manufacturers website states the BT80-45 has a focal length of 597mm. It would be easy to check with some of your eyepieces. try using your"Orion 32mm Plossls yielding 16x with a 3.3 degree fov and a 5.0mm exit pupil."edz
MarkLeica 8x20; Nikon Action 7x35; Vixen Apex Pro 8x42; Orion 15x63; Docter Nobilem 15x60WO Megrez II 80 FD / APM 107mm f/6.5 / Mewlon 210 on DM-6 + Berlebach Planet
Quote:There has been a recent thread about the maximum magnification of the BT100 being limited by aberrations in one of the two barrels. It would interest me to hear more about your experiments at 75x with the Nagler 7mm eyepieces. Is the sharpness noticeably different through either side?
Quote:I'm surprised the optional tripod does not have adjustable height (I believe you said that). I wonder if the head could be mounted on my surveyor tripod?I do have some likely workable EP pairs: A pair of Meade 26 mm Plossls and a pair of LV 10 mm, both with adequate eye relief for me.
Quote:The BT attaches to the mount using a standard 3/8" stud, but the mount base has a custom thread size - Kevin said that the mount would not fit a standard tripod but at some point he would offer an adapter to mate the mount to a 3/8" tripod stud.The BT comes with a pair of 26mm eyepieces (=20x) which Kevin could not substitute with another focal length. It would be interesting to see how the Obie 26mm performs versus the Meade 26mm........