Bahtinov question

[LewisM]

I had Keith Morris in the UK make me up a Bahtinov for the FSQ106ED for f/3.65 - naturally, the slits are a LOT narrower than say an f/5 or larger f.

If I were to use the same Bahtinov on the Fl102S, at f/6.3, will there be any detriment, apart maybe from having a VERY faint pattern to focus on? (it was quite faint at f/3.65 until you zoomed drastically in the preview images)

Or just have him make another? :)

BTW, his Bahtinovs are superb - hard acrylic, that do NOT flex and deform unlike some mass produced ones, which I suspect MAY make the focus a little more precise?

[raymo]

I don't know what Keith Morris charges, but the one I bought from
Bintel for my 8" Newt is very good, and not too flexible. If I remember
rightly, it was $39.
raymo

[blink138]

one of our members here does them extremely well
i got one for my c11 and my brothers canon 300mm f2.8
works great!
i would much rather try one of our members products first
pat

[LewisM]

Thanks guys, but it was not my question - want to know if it is still optically sound to use a Bahtinov with slots for an f/3.65 on an f/6.4 scope -besides making it MUCH harder to see the pattern and maybe needing longer exposure to see it :)

I really can't go past the Morris Bahtinovs - so superbly made. The Farpoint ones I have used previously were less so impressive.