UV/IR Block at F2 - Forums

Topic starter

Sep 11, 2022

Hi,

I shoot with an ASI533mc and have always used a UV/IR cut filter when taking RGB images to help with star bloat.

Does anyone out there use a UV/IR cut filter along with a Hyperstar or RASA and if so could anyone please recommend a suitable filter?

Regards

Steve

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Dan H. M.

Sep 11, 2022 · Edited: Sep 11, 2022

Any old UV/IR cut filter should work. What matters more is the size of the filter because the RASA has such a big light cone, and you will want to avoid reflections. I would think a 36mm filter would work but you may want to try a 2". Either is very affordable.

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Steve Spring

Topic starter

Sep 11, 2022

Thanks for answering. I was thinking about the incident angle and bandshift and did think I was probably worrying too much when I couldn't find any info out there.

Arnie

Sep 11, 2022

Steve:
Thanks for answering. I was thinking about the incident angle and bandshift and did think I was probably worrying too much when I couldn't find any info out there.

Hi,
Angle of incidence is only a consideration for narrowband filters (Ha, Oiii, Sii, etc) where if the angle is too far off from what the filter is designed to pass, some of your light will cut off, with more an more being lost the farther off the angle is. Not a concern with broadband filters (R, G, B) or rejection filters (IR/UV block).
CS,
Arnie

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Rodrigo Roesch

Sep 11, 2022

I use a 2” filter with my RASA 8 when using my color camera ASI 294mc. I think, without the filter you may get blotted stars

Steve Spring

Topic starter

Sep 11, 2022

Thanks everyone for your replies and explanations, much appreciated

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