3-4nm narrowband filters

[R26 oldtimer]

Just sold my baader 7nm narrowband filter set and thinking of an upgrade to an ultra narrowband filter set.

It seems that there are the bulletproof but very expensive choices of Astrodon and Chroma (Antlia possibly falls in the same category) and the more affordable (although not cheap) Baader and Optolong.

I'm currently between those two last options. I've read some ok reviews on the baader (and some not so good but on very fast f ratios) but there isn't much on the Optolong.

I image from bortle 4,5 & 9 locations, my fastest setup is at F/5 and my current camera is a qhy9 (kaf8300). My Neq6 guides okish at 0.7-0.8" regularly and I mostly shoot 600sec subs.

Are there any real life experiences with the optolong 3nm set? With the baader at similar f ratios? Should I be aiming at swamping read noise with 1800sec when using 3nm filters?

[Steve Ward]

Check out Cuiv's videos on narrowband filters , he's very informative and knowledgable ... https://www.youtube.com/c/CuivTheLazyGeek/videos

[Elp]

I've used the baader 7-8nm at f3.9 without issue. Any faster f ratio and you'd need to use the ultra narrowband (unb) f2 filters. I was taking 60s subs. You need to strike a balance between signal to noise, and it depends largely on the target you're trying to image. I don't really see that much difference with the f2 ones, they were bought primarily for the bandpass shift adjustment which you need around that focal ratio or you lose a lot of signal. I did also have a 4.5nm S2 so could compare it to the 6.5nm one, it took longer to get the same amount of signal so I sold it on.

Edited September 29, 2022 by Elp

[R26 oldtimer]

1 hour ago, Steve Ward said:

Check out Cuiv's videos on narrowband filters , he's very informative and knowledgable ... https://www.youtube.com/c/CuivTheLazyGeek/videos

Just saw the video, yet it still deals with the issues of the ultra high speed (preshifted) filters. My focal ratios are more "friendly" at F/5 or higher.

What about the 3nm optolongs? Any hand on experience? Anyone? 😊