Is it a mistake to combine Ha-oiii 12nm with oiii-Sii 6nm filters?

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Gabriel avatar

Hi, everything is in the title.

Is it a mistake to combine Ha-oiii 12nm + oiii-Sii 6nm ?

I’d like to add an additional filter to my set-up, a dual band oiii-sii.

It is difficult in France to find a 12nm dual band in o3-s2, and I received an offer for an askar D2, at 6nm FWHM.

For you, is it a mistake to combine 12nm + 6nm ?

Thanks a lot

Gabriel

andrea tasselli avatar
No, why should it be?
Stjepan Prugovečki avatar

Hi, no, it is not.

Cs

Morian avatar
In this hobby there are no rules about what you can and can't do.
Just do what you like.
Well Written
BlackStarsAstro avatar

Never say never. Thats how we innovate and move the hobby forward.

Lynn K avatar

I wouldn’t see a problem unless the 12nm was taken in a more light polluted skies and nosier. I can certainly see an increase in background noise level from a 12nm Ha as opposed to a 6nm Ha from my Bortle 7 backyard.

I have a IDAS NBZ filter. they are 12nm HA & OIIII. I used it with a FSQ85ED at F3.9/ASI2600MC at my clubs dark site (Bortle 4). I tried to add additional data from my backyard. The increase in noise level and gradients were very noticeable and I did not use that data. Poorer sky transparency could have also been a factor, but I didn’t notice any major difference.

Lynn K.

Helpful
Gabriel avatar

Lynn K · Oct 18, 2025, 08:39 PM

I have a IDAS NBZ filter. they are 12nm HA & OIIII

That’s very interesting since I also have the IDAS NBZ. My question is more about the loss of finesse while stacking 12nm OIII with 6nm OIII.

I know that it’s possible to blend both but I guess it’s better to have Ha-oiii and oiii-Sii both in 6nm right ? I love my NBZ, it performs really well but thanks to Cuiv the lazy geek, I’m almost sure the D1 would work at least as well as the NBZ.