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Comparing duo-band filters

ZWO Duo-Band Filters Acquisition Duo-Narrowband Deep Sky
Tareq Abdulla
•29 replies•1.8k views
Philippe Barraud avatar
Philippe Barraud avatar
Duo-band filters are very useful for imaging nebulae with light pollution or… Moonlight, when using color cameras.
Since the brands select narrowbands (H alpha and Oxygen III)  in slightly different wavelenghs, the results can be different too.
I have compared Optolong LXtrem filter and ZWO duo-band filter.
With the latter, I get a little more signal, more colors, but the stars are only slightly reduced. With the LXtrem, the stars are nicely reduced, but the signal and the colors are weaker.
So, globally, I am a bit disappointed by the Xtrem, which is rather expensive. I have better images with the ZWO duo-band, and since I have more signal, I can go deeper in processing. As for the stars, I can reduce them with StarShrink.
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Howard Richard avatar
Howard Richard avatar
I have gone through most of the Optolong series. I find the L-Ultimate to be better than the L-Extreme… I can image with a full moon and get usable data.

I have not tried the ZWO filters.
Tony Gondola avatar
Tony Gondola avatar
I have the 6nm dual band SVBony filter and I'm very happy with it. I can't see anything on paper that would suggest that the L-Extreme wouldn't give similar results. The band passes are at the same frequencies as the SVBony filter, just 7nm wide verses 6nm. The thing is, it's not unusual for these filters not to meet the published specifications. Cuiv the Lazy Geek from you tube tested a bunch of popular filters and found that a lot of them didn't perform as advertised

https://www.youtube.com/watch?v=VkSvpOLlD2Y
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Alan Mason avatar
Alan Mason avatar
I've been using the ALP-T 5nm for the past few months, and it has produced great results. However, I need at least 65 deg of separation from the full moon for clean data.

STC duo was a good filter, but had some halos around typical bright stars (alnitak, 52 cygni)
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Luc Viatour avatar
Luc Viatour avatar
ersonally, I use an IDAS NBZII filter. The stars are finely reduced, the transmission is very good, I get a lot of signal without having to do very long acquisition times. The quality of IDAS Japanese filters is very consistent.

After a 5-hour exposure with an unfiltered Nikon Z7, WR134 appears.
https://www.astrobin.com/full/3l89hi/F/
Alex Nicholas avatar
Alex Nicholas avatar
I believe the Askar D1 and D2 are the best pair of dual narrowband filters. Optolong L-extreme and L-ultimate are the most popular but for me, the halos were unacceptable.
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Richard Carande avatar
Richard Carande avatar
Antlia has a newish Ha/Oiii dual-band filter, with (presumably) 3nm pass bands.  I have used it a few times, and it seems to work well – a lot better than my prior L-eXtreme filter.  No halos to speak of in the Antlia.  I'm surprised I haven't seen more influencer discussion on this filter.
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Dean Linic avatar
Dean Linic avatar
Alex Nicholas:
I believe the Askar D1 and D2 are the best pair of dual narrowband filters. Optolong L-extreme and L-ultimate are the most popular but for me, the halos were unacceptable.

Askar D1/D2 are top pick at the moment. I did try almost all other brands Antila, Optolong, SVvBony, Altair, Player One  in the end only Askar is not producing halo around Alnitak. Signal is strong and contrast is fine.
Optolong is far worst pick, halos are so bad that I think they are not in the same league.
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Dale Penkala avatar
Dale Penkala avatar
I did a comparison about 2 years ago with my NBZ and my ALP-T filter. Tried to keep everything identical/consistent throughout the process. I use BOTH filters and really like the results that I get with them.

For anyone interested here is my findings: https://app.astrobin.com/u/DalePenkala?i=uz2syz#gallery

The ALP-T is excellent but very dark so I find that I have to go out to 600s-900s subs on very faint objects.

Just my 2 cents.
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Tareq Abdulla avatar
Tareq Abdulla avatar
Great, let's list it here:

ZWO Duo Band
L-eXtreme
L-Ultimate
SVBony Dual Band
Antlia ALP-T 5nm
IDAS NBZII
Askar D1 and D2
Player One dual band

Anything else???
Richard Carande avatar
Richard Carande avatar
Tareq Abdulla:
Great, let's list it here:

ZWO Duo Band
L-eXtreme
L-Ultimate
SVBony Dual Band
Antlia ALP-T 5nm
IDAS NBZII
Askar D1 and D2
Player One dual band

Anything else???

As I mentioned in a comment above, Antlia also has a ALP-T 3nm dual-band filter now.
Rick Veregin avatar
Rick Veregin avatar
Living under Bortle 8 skies, I have tried many filters. For NB HO, the best filter I have used is the L-Ultimate, much better than L-eXtreme or any other filter I have tried. 

I thank James Thompson for his wonderful scientific investigation of NB filters, really amazing studies, I use his work to guide me! Before you decide on any filter, I suggest to you go to Research Gate and look at his work analzying filters. He has looked at every filter you might think of, as far as I can see. A recent article by him finds the L-Ultimate is the best for HO NB by a big margin, the article is here: https://www.researchgate.net/publication/364965907_L-uLtimate_Filter_Comparison_Test

Do realize that NB filters cut out most of the light, so the signal you see will be lower, but the contrast and S/N will be better for the NB signals.
CS
Rick
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Tareq Abdulla avatar
Tareq Abdulla avatar
Richard Carande:
Tareq Abdulla:
Great, let's list it here:

ZWO Duo Band
L-eXtreme
L-Ultimate
SVBony Dual Band
Antlia ALP-T 5nm
IDAS NBZII
Askar D1 and D2
Player One dual band

Anything else???

As I mentioned in a comment above, Antlia also has a ALP-T 3nm dual-band filter now.

What i hate about Antlia is that they always coming late, and prices isn't much promising, i mean for same price i can go with other brands too, i bought L-Ultimate before Antlia think about producing or releasing 3nm dual band in markets, so i won't just sell L-Ultimate to get Antlia one, even Askar made those 3nm before but they aren't accurate 3nm, and Antlia is trying to price like something cheaper and something else more pricey, their CaK tool is way cheap than Lunt i bought, too late, but i will see if i can find Antlia 3nm dual band in 1.25" or 36mm size.
Tareq Abdulla avatar
Tareq Abdulla avatar
Rick Veregin:
Living under Bortle 8 skies, I have tried many filters. For NB HO, the best filter I have used is the L-Ultimate, much better than L-eXtreme or any other filter I have tried. 

I thank James Thompson for his wonderful scientific investigation of NB filters, really amazing studies, I use his work to guide me! Before you decide on any filter, I suggest to you go to Research Gate and look at his work analzying filters. He has looked at every filter you might think of, as far as I can see. A recent article by him finds the L-Ultimate is the best for HO NB by a big margin, the article is here: https://www.researchgate.net/publication/364965907_L-uLtimate_Filter_Comparison_Test

Do realize that NB filters cut out most of the light, so the signal you see will be lower, but the contrast and S/N will be better for the NB signals.
CS
Rick

I am one of those lucky people in the world maybe that didn't buy L-enhance and L-extreme only to upgrade to L-Ultimate, i just waited so long and bought L-Ultimate under nice price new, and i didn't wait longer to see Antlia making one with 3nm instead of their 5nm, for my Bortle 9 i prefer 1nm over 5nm, so 3nm should be a natural choice regardless of the optics quality, but many people swear by NBZ, i don't know if i should buy this also if i am thinking about using my fast optics mainly my DSLR lenses at f/1.4 up to f/2.8.
BFR avatar
BFR avatar
I have the stc clip in for sony and the idas NBZII (drop in version, to be combined with my sony a7s modded). It has no halos, gets a lot of info, and can be used at wide apertures. I attach a pano done with it, where I only combined 1 filttered photo of a about two minutes per panel, with one 15 second photo per panel with no filter (to get RGB).



BFR avatar
BFR avatar
I have the stc clip in for sony and the idas NBZII (drop in version, to be combined with my sony a7s modded). It has no halos, gets a lot of info, and can be used at wide apertures. I attach a pano done with it, where I only combined 1 filttered photo of a about two minutes per panel, with one 15 second photo per panel with no filter (to get RGB).




*** 
Here one taken with the stc astro duo narrowband filter, with similar exif to the previous one ***
Luc Viatour avatar
Luc Viatour avatar
Star halos are beautiful with the NBZII, but most importantly, it has very good transmission. There's a lot of signal with reasonable exposure times. For example, WR134, which is difficult to capture without very long exposure times, I was able to get in 4 hours and 30 minutes of exposure with a 120mm F7 refractor and a modified Nikon Z7.
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Rick Veregin avatar
Rick Veregin avatar
Tareq Abdulla:
Rick Veregin:
Living under Bortle 8 skies, I have tried many filters. For NB HO, the best filter I have used is the L-Ultimate, much better than L-eXtreme or any other filter I have tried. 

I thank James Thompson for his wonderful scientific investigation of NB filters, really amazing studies, I use his work to guide me! Before you decide on any filter, I suggest to you go to Research Gate and look at his work analzying filters. He has looked at every filter you might think of, as far as I can see. A recent article by him finds the L-Ultimate is the best for HO NB by a big margin, the article is here: https://www.researchgate.net/publication/364965907_L-uLtimate_Filter_Comparison_Test

Do realize that NB filters cut out most of the light, so the signal you see will be lower, but the contrast and S/N will be better for the NB signals.
CS
Rick

I am one of those lucky people in the world maybe that didn't buy L-enhance and L-extreme only to upgrade to L-Ultimate, i just waited so long and bought L-Ultimate under nice price new, and i didn't wait longer to see Antlia making one with 3nm instead of their 5nm, for my Bortle 9 i prefer 1nm over 5nm, so 3nm should be a natural choice regardless of the optics quality, but many people swear by NBZ, i don't know if i should buy this also if i am thinking about using my fast optics mainly my DSLR lenses at f/1.4 up to f/2.8.

For fast optics the LUltimate is not good, too narrow and off band at that f/ratio, so you need a different filter for that.
Tareq Abdulla avatar
Tareq Abdulla avatar
Rick Veregin:
Tareq Abdulla:
Rick Veregin:
Living under Bortle 8 skies, I have tried many filters. For NB HO, the best filter I have used is the L-Ultimate, much better than L-eXtreme or any other filter I have tried. 

I thank James Thompson for his wonderful scientific investigation of NB filters, really amazing studies, I use his work to guide me! Before you decide on any filter, I suggest to you go to Research Gate and look at his work analzying filters. He has looked at every filter you might think of, as far as I can see. A recent article by him finds the L-Ultimate is the best for HO NB by a big margin, the article is here: https://www.researchgate.net/publication/364965907_L-uLtimate_Filter_Comparison_Test

Do realize that NB filters cut out most of the light, so the signal you see will be lower, but the contrast and S/N will be better for the NB signals.
CS
Rick

I am one of those lucky people in the world maybe that didn't buy L-enhance and L-extreme only to upgrade to L-Ultimate, i just waited so long and bought L-Ultimate under nice price new, and i didn't wait longer to see Antlia making one with 3nm instead of their 5nm, for my Bortle 9 i prefer 1nm over 5nm, so 3nm should be a natural choice regardless of the optics quality, but many people swear by NBZ, i don't know if i should buy this also if i am thinking about using my fast optics mainly my DSLR lenses at f/1.4 up to f/2.8.

For fast optics the LUltimate is not good, too narrow and off band at that f/ratio, so you need a different filter for that.

Ah ok, i will look around at some choices then, thank you
Dunk avatar
Dunk avatar
Tareq Abdulla:
Ah ok, i will look around at some choices then, thank you


I can recommend the Antlia Golden.

They also have a "Fast" version which I've found works well on my Epsilon @ F/3.2 as well as a Samyang 135 @ F/2.
Tareq Abdulla avatar
Tareq Abdulla avatar
Dunk:
Tareq Abdulla:
Ah ok, i will look around at some choices then, thank you


I can recommend the Antlia Golden.

They also have a "Fast" version which I've found works well on my Epsilon @ F/3.2 as well as a Samyang 135 @ F/2.

Great, i think once i buy this one if i choose it and also Antlia OIII 3nm 2" then i will officially close the DSO filters, i won't buy a dual band of OIII+SII one because i already have many mono cameras, so i might only use dual band for Ha+OIII only, thank you very much.
Jeroen Lagerwerf avatar
Jeroen Lagerwerf avatar
I have the stc clip in for sony and the idas NBZII (drop in version, to be combined with my sony a7s modded). It has no halos, gets a lot of info, and can be used at wide apertures. I attach a pano done with it, where I only combined 1 filttered photo of a about two minutes per panel, with one 15 second photo per panel with no filter (to get RGB).




*** 
Here one taken with the stc astro duo narrowband filter, with similar exif to the previous one ***

I have the stc astro duo narrowband filter too, but haven't had the chance to use it due to the weather. I have to say it's a bit of a fiddly job to clip it in (not to mention to get it out), but looking atyour photo it looks very promising!
Wei-Hao Wang avatar
Wei-Hao Wang avatar
Tareq Abdulla:
Great, let's list it here:

ZWO Duo Band
L-eXtreme
L-Ultimate
SVBony Dual Band
Antlia ALP-T 5nm
IDAS NBZII
Askar D1 and D2
Player One dual band

Anything else???

STC Duo NB
It's the first of such filters.

It does have halos on brighter stars, but this never bothered me.  See a comparison (with regular RGB) here.
Tareq Abdulla avatar
Tareq Abdulla avatar
Wei-Hao Wang:
Tareq Abdulla:
Great, let's list it here:

ZWO Duo Band
L-eXtreme
L-Ultimate
SVBony Dual Band
Antlia ALP-T 5nm
IDAS NBZII
Askar D1 and D2
Player One dual band

Anything else???

STC Duo NB
It's the first of such filters.

It does have halos on brighter stars, but this never bothered me.  See a comparison (with regular RGB) here.

Ok, i forgot to add it although someone mentioned it in the comments, thank you
Observatório Astrográfico do Boqueirão avatar
Observatório Astrográfico do Boqueirão avatar
Tareq Abdulla:
Great, let's list it here:

ZWO Duo Band
L-eXtreme
L-Ultimate
SVBony Dual Band
Antlia ALP-T 5nm
IDAS NBZII
Askar D1 and D2
Player One dual band

Anything else???



Altair Dualband Ultra