Methane filter?

[TareqPhoto]

Hi all,

I keep my mind on having Chroma CH4 filter, but i also see Baader isn't a bad option as well, but i want anyone here to help me to answer my question.

ZWO, Baader and Chroma are all CH4 filters at 889mm, but, why they have different FWHM? 

ZWO = 20nm

Baader = 8nm

Chroma = 18nm

This is the only filter that is left for my filter wheel, so i am trying to think about it as i may buy it on June or July depends on my situations, so from now i have to decide between the two, thickness doesn't matter because i will re focus always with different filters rather than LRGB anyway.

[andrew s]

I don't  know why they are different but the wider bandwidth is better unless you have a large telescope .  At 889nm it is imaging only as it is into the IR band. Better with reflective optics too.

Regards Andrew