Is there a general consensus about what is the best dual band filter to use on an OSC camera for a Hubble palette, besides the Ha/OIII?
Would that be an SII/OIII or an SII/Hb?
Hello, Willlem!
As far as I know, you can create a synthetic SII channel if you want to use the Ha-OIII filter only. But usually, you would use the SII-OIII filter to capture SII.
Hope this helps. Clear Skies!
Interactive Sky · Jun 2, 2026 at 06:07 PM
Hello, Willlem!
As far as I know, you can create a synthetic SII channel if you want to use the Ha-OIII filter only. But usually, you would use the SII-OIII filter to capture SII.
Hope this helps. Clear Skies!
Thanks, a synthetic SII sounds intriguing. One would think that the SII signal would be independent from the other two?
So your advice is the SII/OIII over the SII/Hb.
Thanks very much, and clear skies to you as well!
Willem Jan Drijfhout · Jun 2, 2026, 03:46 PM
Is there a general consensus about what is the best dual band filter to use on an OSC camera for a Hubble palette, besides the Ha/OIII?
Would that be an SII/OIII or an SII/Hb?
I would go quadro-chromic and get an Antlia SII/Hb DNB. Not cheap though…
I don’t think they are comparable, one is Hbeta-SII and the other is OIII-Halpha. If you mean the ALP-T then it is much better than the L-Extreme but then one is 5nm and the other is 7nm (in fact even more). Performance with fast systems is the real discriminant here and there is no real alternative to Antlia for that.
If you don’t want halos Antlia is your only option really. Others are “virtually” halo-free (real YT influencer-speak) - and you will be unpleasantly surprised.
Willem Jan Drijfhout · Jun 2, 2026, 06:18 PM
Thanks, a synthetic SII sounds intriguing. One would think that the SII signal would be independent from the other two?
It is, in fact, independent. I’ve seen many tricks trying to replicate the “SII Feel” but they lack the depth of a true independent third channel.
This is just an attempt at it (SVbony SV220 7nm Ha/Oiii):
📷 image.png
This is a “true” SHO using the filter from above and its Sii/Oiii sibiling:
📷 image.png
Nothing bad using just an Ha/Oiii but adding light from the Sii/Oiii has the additional benefit of increasing the Oiii signal.
Rafał Szwejkowski · Jun 2, 2026, 11:07 PM
If you don’t want halos Antlia is your only option really. Others are “virtually” halo-free (real YT influencer-speak) - and you will be unpleasantly surprised.
Askar’s D1/D2 are stunningly good and 100% halo free in my testing… That said, not sure how great they are on a fast optical system.. I only used them as fast as f/4.8.
Furthermore, remembering that if you go Ha/OIII + SII/Hb, you’re pidgeon-holing your self into a deeply annoying truth about the night sky…
OIII and SII are incredibly sparse by comparison to Ha. Ha rules the night sky… If you’re only capturing OIII data while also capturing Ha, you will either end up considerably weak OIII data, or you’ll end up sacrificing SII or OIII in favor of the other…
If you get Ha/OIII and SII/OIII, you can shoot 4~5h with Ha/OIII, then 10h with SII/OIII, you’ll have 5h Ha, 10h SII and 15h OIII, which will typically mean your SII and OIII won’t get swamped by Ha data…
YMMV, but, As nice as getting the Hb is, I would prefer to double down on OIII… or in a perfect world where the sky was always clear and you have no other responsibilities, get all 3…. 5h Ha/OIII, 10h SII/OIII, 5h SII/Hb resulting in 5h Ha, 15h OIII, 15h SII, 5h Hb… then go to town with your data…