I'm considering purchasing an 81mm aperture refractor telescope to use with my Quark Chromosphere filter in order to achieve a wider field of view compared to my Sky Watcher Evostar 150.
I have two telescopes in mind: the William Optics Zenithstar 81 (doublet) with an f6.9 focal ratio, and the William Optics GT81 (triplet) with an f5.9 focal ratio. I am inclined towards the GT81 due to its shorter focal length, but I'm unsure if its f5.9 ratio would have a negative impact on the performance of the Quark filter.
Thank you very much in advance!
Eduardo Schaberger Poupeau
What is better, f5.9 or f6.9, to use with a Quark filter
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Re: What is better, f5.9 or f6.9, to use with a Quark filter
Go for the f / 6.9 one. You want to achieve at least something like f30 at the etalon. Short focal length refractors are not a thing when it comes to contrasty h-alpha. f/35-40 is even better for the etalon performance.
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H-a: Quark Chromosphere with BF mod
WL: Antlia 500nm/ 3nm, 393 nm/ 3nm
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H-a: Quark Chromosphere with BF mod
WL: Antlia 500nm/ 3nm, 393 nm/ 3nm
Ca-K: homebrew (includes 2x 1.5A filters, thanks Apollo)
Player One Apollo Max + Mars MII
Barlows:
-2x Gerd Düring 2.7x
-2x TMB 1.8x
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Re: What is better, f5.9 or f6.9, to use with a Quark filter
Thanks a lot for the advice, Dennis! I really find it super helpful!
- marktownley
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Re: What is better, f5.9 or f6.9, to use with a Quark filter
The f6.9 scope will deliver a more contrasted view with the Quark
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