What is the best 8 inch SCT OTA?

[russ.will]

Ah! You bought that one off UKABS.

I love mine and it's the only scope I've ever owned that I would say is over-mounted. Seriously, I've been out in winds with it, that I wouldn't even have bothered with with my former open truss dobs. It just doesn't budge.

Now get reading on the auto alignment and benefits of re-calibrating the sensors after clearing the previous owners data.

Russell

[Zeffer]

Will do! Yes I did buy that one, another true gentleman to deal with. Any other tips gratefully received. Especially if you have an EP suggestion for wide as possible pin sharp viewing!

[russ.will]

See signature! 

Joking aside, given the 38mm exit aperture at the rear of an 8" SCT, the 40mm in my signature *should* vignette at the edges, although in practice, if it does, I've yet to notice it. Given that this is either a minimal artifact, or I'm just completely insensitive to it, then anything from a SW 38mm Panaview and up (in price) should give nice 50x views and only a 3.8mm exit pupil.

As far as tips? Weasners SCT page.

Russell

[YKSE]

I agree with Russ, aneyepiece with 46mm field stop doesn't vignette despite the 38mm rear port.

Looking for vignetting is easiest to be done in daylight pointing the scope to sky. Some of my eyepieces vignetted in daylight, but not in nightly use. But 40mm Aero with 46mm field stop doesn't vignette in my C8.

By what I've read on other site, our eyes are not very sensitive to vignetting, a 50% light fall off in the edge is usually not detectable to our eyes.