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filter size and impact on vignetting Takahashi Epsilon 160 · Nick Grundy · ... · 3 · 111 · 2

Supro 4.37
Nick Grundy
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Hi all, I've been using my 160ed for some time now with an EFW and 50mm filters. (directly attached, asi2600+EFW) That puts the filters about 20mm away from the sensor. (i think)

in calculating the angle of incidence at the edges, at F3.3, even a 50mm filter can cause vignetting? Is my math correct? (530mm Focal length, F3.3, full frame sensor) A diameter of ~53mm would steer clear of causing vignetting (if that was a size)

Maybe this is obvious to everyone else? i'm sure flats could help correct it, but just wondering if i'm missing something in the math here

CS!
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andreatax 9.89
andrea tasselli
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Supro 4.37
Nick Grundy
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sorry, I should have noted that I was looking at this in favor of shifting to a asi6200mm/mc

I used the same calculator and it resulted in a recommendation of 48mm, I just did the math manually though and it seemed larger. 

Here's where I was coming from. This is wrong?image.png
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andreatax 9.89
andrea tasselli
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Are you using AI (tan(arctan(theta)) = theta = 1/(2*F/#))? The (mine) manual calculation gives 49 mm. I guess the difference is in what is that is assumed to be be the light cone angle. This is however purely academic as a standard 2" filter is significantly smaller than that, usually between 44 and 45 mm, mounted. You want 50mm unmounted filters for that sensor and scope combination.
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