Quote:
Originally Posted by koputai
The theoretical longest eyepiece is fl=(scope_f x 7mm).
So, in your f5 Newt it is 5 x 7mm = 35mm.
I use a 35mm in my f5 with no problems.
Cheers,
Jason.
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That is assuming your pupil reaches 7 mm right? So if you eye only gets to 6 or so, them you'd be limited to 30 mm in an F5 scope? (Dunno where I got my 32 mm from as my scope is F5 as well! Must have remembered it wrong)
As for the coma, I think it would be the AFOV that governs that rather than the diameter of the eyepiece. Presumably the field stop / size of objective lens in the 1.25 would limit the AFOV??
You can probably tell that this isn't really my area of expertise....
My understanding is that with a fast (F5) scope you basically can't have a wide AFOV without corrective lenses in the eyepiece. The better the correction (e.g. Nagler/Ethos etc.) the higher the price.
Away from the very edge I wouldn't say that the coma in my MAS Ultra-Wide is really distracting, but it is there.