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Which UV/IR cut filter should I get?

Equipment UV/IR Cut Filters
2 replies•141 views
Which one?
Multiple choice poll 5 votes
20% (1 vote)
40% (2 votes)
40% (2 votes)
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Menelaos avatar
Menelaos avatar
Hello guys. I am looking into purchasing a uv/ir filter and there are a few different options about how much of the spectrum the let in (L1,2,3). What difference would L1 from L2 and L3 make? Will I be able to tell the difference in an image? How do I choose which one to get?
thank you.
Tim Hawkes avatar
Tim Hawkes avatar
My understanding is that the choice depends on your telescope and optical path. If you are using say a Newtonian with not much difraction from reducers etc then the widest band pass (L1 ?)  might be appropriate. If on the other hand you have a relatively poorly corrected ED refractor doublet which might suffer from bloom at the blue end of the spectrum then a tighter band pass would be better (L3?)

Tim
Dan Watt avatar
Dan Watt avatar
Hello guys. I am looking into purchasing a uv/ir filter and there are a few different options about how much of the spectrum the let in (L1,2,3). What difference would L1 from L2 and L3 make? Will I be able to tell the difference in an image? How do I choose which one to get?
thank you.

I mostly image with newtonians so star bloat from chromatic aberration is not an issue. Occasionally I do use my camera with camera lenses or short refractors. I’ve found the L2 is a great all rounder. L3 would be nice for some refractors or older lenses that have worse CA, and L1 would be good for purely reflective optics. That said, I don’t feel like I’m missing much by using the L2 with my newt.
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