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May I ask where the line is drawn for "fast' newtonians? Like you Mark, I have been around astronomy for many years. 40 years ago I would have said an F6 was standard, perhaps bordering on fast, with plenty of F7s and F8s around. Now we appear to have F4.5 as standard. To me an F 3.5 is "very fast" and I am pretty sure I would find the views annoying if using a longer f.l. eyepiece. The longest eyepiece I use is 27mm, even then I find out of focus central spot annoying.
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