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My first narrowband filters. 3nm or 6nm?

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#1 vland

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Posted 24 June 2022 - 01:19 AM

I want to start narrowband imaging. I'll purchase a set of Ha / Oiii / Sii

Considering my equip :

 

- bortle 5 sky 

- FSQ85 wide field astrograph

- apochromatic 150/1200

- qhy268M (sony IMX571 with 3.75 micron/pixel)

 

 

What filters would you suggest to start with, a set of 3nm or a set of 6nm?

I'd like to understand a list of pro/cons of both

 

Options I considered, price descending

  • chroma set 3nm
  • antlia pro 3nm
  • astronomik maxFR set 6nm

 

thank you

 


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#2 pyrasanth

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Posted 24 June 2022 - 03:08 AM

I would always buy the OIII filter at 3 nm and the Hydrogen alpha at 5 or 6. The 3 nm HA filter will remove the nitrogen emission line which can help brighten up the data being captured by a wider filter however you might wish to be a purist and capture pure HA.

 

Increasingly i've started to capture much less SII data since I've changed to a 4.5 nm Baader filter- I think I should have kept at a 5-6.

 

Your filter choices are good- I would consider the new Baader CMOS optimised filters as well. They are very good. I think your most important filter will be a good OIII at 3nm as it works well even under a bright moon- however the Chroma version is really expensive but it is a classy filter. I have the 50x50 square Chroma OIII filter and it costs as much as a good small refractor!



#3 jeffcrilly2

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Posted 24 June 2022 - 03:42 AM

I can't speak to the list you outlined... however...

 

I have an older set of Baader narrowband filters ... iirc 6nm... and a set of the more recent "cmos optimized" 3nm/4nm narrowband filters.

 

I prefer the 3nm/4nm hands down, and wouldn't waste my time with the 6nm filters... I did a brief comparison of the Baader 3nm Ha vs 6nm Ha, and it sure looked clear to me the 3nm results just "looked better".   

 

-jeff



#4 Rasfahan

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Posted 24 June 2022 - 04:12 AM

If price is no concern, get the Chroma 3nm. But I‘ld stick with 5nm for Ha, too. Not so much for the N-II (very faint) but because you might get a longer FL scope sometime and the wider bandpass helps capturing Ha in galaxies that are redshifted.

If price is at all a concern, in Bortle 5 you will get great results with the MaxFR 6nm, too. In my testing (Bortle 5-6) they show no halos or reflection issues. Full moon OIII is still well possible for the brighter targets.

 

From what I‘ve seen I wouldn‘t consider the Baader at all. Don‘t know anything about the Antlia.


Edited by Rasfahan, 24 June 2022 - 04:13 AM.


#5 Eyeroll1952

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Posted 24 June 2022 - 07:27 AM

From what I‘ve seen I wouldn‘t consider the Baader at all. 

Can you expand on your dislike for the Baader filters?

 

Thanks,

 

Paul



#6 vland

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Posted 24 June 2022 - 07:45 AM

Can you expand on your dislike for the Baader filters?

 

Thanks,

 

Paul

I also heard different opinions about Baader narrowband.

My local astronomy shop says "don't buy those". But I don't consider his opinion because he doesn't sell them....

Cuiv the lazy geek (youtube channel) had problems with said filters (the fast versions) and spectrum analysis wasn't compliant to the filter specs.

 

Also, my current set of Baader LRGB has quite an amount of halos, especially in the blue channel and I'm not very happy about that

 

Back in topic... I see a lot of difference suggestions... it's really difficult to make a choice tongue2.gif


Edited by vland, 24 June 2022 - 07:48 AM.


#7 Eyeroll1952

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Posted 24 June 2022 - 08:34 AM

I also heard different opinions about Baader narrowband.

My local astronomy shop says "don't buy those". But I don't consider his opinion because he doesn't sell them....

Cuiv the lazy geek (youtube channel) had problems with said filters (the fast versions) and spectrum analysis wasn't compliant to the filter specs.

 

Also, my current set of Baader LRGB has quite an amount of halos, especially in the blue channel and I'm not very happy about that

 

Back in topic... I see a lot of difference suggestions... it's really difficult to make a choice tongue2.gif

Interesting. I have had a set of Baader 6 nm filters on backorder for a while. I selected them as I was seeing multiple good reviews claiming they were at least better than ZWO filter sets. Yes, this is tough and may be a matter of how much money one is willing to spend... 

 

Paul



#8 Rasfahan

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Posted 24 June 2022 - 08:48 AM

Can you expand on your dislike for the Baader filters?

 

Thanks,

 

Paul

Basically, what Vland says. Results with them seem to be either very dependent on the imaging system used or there is high inter-sample variation. I really like a lot of the things Baader produces, had great experience with their service, own a lot of their accessories and bought my 10M mount from them… but their filters seem to be hit and miss. A pity, because the price seems right.



#9 Eyeroll1952

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Posted 24 June 2022 - 09:00 AM

Basically, what Vland says. Results with them seem to be either very dependent on the imaging system used or there is high inter-sample variation. I really like a lot of the things Baader produces, had great experience with their service, own a lot of their accessories and bought my 10M mount from them… but their filters seem to be hit and miss. A pity, because the price seems right.

Thanks. I like the price too and have a hard time spending 2-5 times as much on filters from some of the other suppliers. But I also don't want to hate myself later for being too cheap... 



#10 schellaj

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Posted 24 June 2022 - 09:50 AM

Baader is, in general, a good product. I had a full set of 36mm LRBGSHO (before the latest version) and they worked fine. Yes, there were halos on brighter stars (strongest in the B and OIII), but you can minimize these in post-processing.

 

I bought the OIII CMOS-optimized in the fall, and it worked very well. No halos. However, a number of people were reporting halos, even with the CMOS-optimized ones. 

 

Since the price was now higher, and much closer to the price of Chroma or Astrodon, I replaced the rest of filters with Astrodons. Not too many people complain about the quality of these.

 

Ultimately, there is a chance you will get a filter that does not meet specs.  A higher chance when you go with more mass produced, like Baader, Astronomiks, ZWO, etc..

 

It all comes down to how much to you want to play around with your images in post-processing and how much money you have to spend (and what you want to spend it on).

 

Cheers,

 

Jason



#11 photobiker

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Posted 24 June 2022 - 09:51 AM

I just picked up a full set of Antlia filter to replace the ZWO filters.  Agena was having a little sale on them so I got 3nm O3 and 4.5nm S2 and Ha and a set of LRGB in 31mm.  It was a bunch of dollars, not as much as I could have spent on say Chroma which are way above my pay grade, maybe one day.  I feel like I have too much money tied up I telescopes and cameras to use maybe mediocre filters not to mention the time involved.  Will I be able to tell the difference?  I don't know that I have enough experience or inventory of images to be able tell.



#12 schellaj

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Posted 24 June 2022 - 09:53 AM

And to answer the original question,  3mm vs 6mm - I think in a B5 zone, 6mm is OK. The benefit is a bit more light coming through the filter = less noise = less imaging time.  Light pollution is not really an issue in NB for either 3 or 6 mm unless you are in a B8-9 zone.

 

Jason 



#13 rockstarbill

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Posted 24 June 2022 - 01:16 PM

Baader is, in general, a good product. I had a full set of 36mm LRBGSHO (before the latest version) and they worked fine. Yes, there were halos on brighter stars (strongest in the B and OIII), but you can minimize these in post-processing.

I bought the OIII CMOS-optimized in the fall, and it worked very well. No halos. However, a number of people were reporting halos, even with the CMOS-optimized ones.

Since the price was now higher, and much closer to the price of Chroma or Astrodon, I replaced the rest of filters with Astrodons. Not too many people complain about the quality of these.

Ultimately, there is a chance you will get a filter that does not meet specs. A higher chance when you go with more mass produced, like Baader, Astronomiks, ZWO, etc..

It all comes down to how much to you want to play around with your images in post-processing and how much money you have to spend (and what you want to spend it on).

Cheers,

Jason


Astronomik filters aren't mass produced and come with a 10 year warranty and a no halo guarantee from Gerd Neumann.

#14 Rouzbeh

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Posted 24 June 2022 - 10:32 PM

I might get a set of Astronomik 6nm and compare them head to head with the Chroma 3nm soon.


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#15 rockstarbill

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Posted 24 June 2022 - 10:50 PM

I might get a set of Astronomik 6nm and compare them head to head with the Chroma 3nm soon.

For systems F4 and above the 3nm Chroma will be better. Below F4 and without the pre-shifted versions from Chroma, the 6nm Astronomiks are much better.


Edited by rockstarbill, 25 June 2022 - 12:23 AM.


#16 chimerasaurus

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Posted 24 June 2022 - 11:18 PM

For systems F4 and above the 3nm Chroma will be better. Below F4 and without the pre-shifted versions from Chroma, the 6nm Astrronomiks are much better.


This is encouraging. I have an unused set of the Atronomiks collecting dust while my RASA 8 is with Celestron.
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#17 rockstarbill

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Posted 25 June 2022 - 12:24 AM

This is encouraging. I have an unused set of the Atronomiks collecting dust while my RASA 8 is with Celestron.

I am using the 6nm MaxFR Astronomiks right now as we speak, on my F3.3 Epsilon E160ED. Data is sublime. smile.gif


Edited by rockstarbill, 25 June 2022 - 12:24 AM.


#18 Rouzbeh

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Posted 25 June 2022 - 01:13 AM

I'm currently at f4.75.

Id be curious to see the difference in numbers, side by side.

Ill haven't started anything yet.

 

My Oiii does show a ghost reflection with the Chroma now, will flip it in the next imaging session to see if that makes a difference.



#19 rockstarbill

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Posted 25 June 2022 - 02:40 AM

I'm currently at f4.75.

Id be curious to see the difference in numbers, side by side.

Ill haven't started anything yet.

 

My Oiii does show a ghost reflection with the Chroma now, will flip it in the next imaging session to see if that makes a difference.

Wont make any difference friend.



#20 Jon Rista

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Posted 25 June 2022 - 02:48 AM

I want to start narrowband imaging. I'll purchase a set of Ha / Oiii / Sii

Considering my equip :

 

- bortle 5 sky 

- FSQ85 wide field astrograph

- apochromatic 150/1200

- qhy268M (sony IMX571 with 3.75 micron/pixel)

 

 

What filters would you suggest to start with, a set of 3nm or a set of 6nm?

I'd like to understand a list of pro/cons of both

 

Options I considered, price descending

  • chroma set 3nm
  • antlia pro 3nm
  • astronomik maxFR set 6nm

 

thank you

I say go for the narrowest you can, unless you explicitly need to image at very fast f-ratios. I image with 3nm filters at f/4, and have never had any notable issues with spectral shift (I'm sure there is a bit, but its never been problematic in a way I've ever noticed.) 

 

I also STRONGLY recommend getting the same bandwidth for all filters. One of the things I've noticed in a lot of people's NB image is often notably different star sizes across channels, which can screw with stellar color and star processing. I've always had 3nm filters, and have found that with proper channel alignment (I generally avoid linear fit, and prefer a simpler additive linear alignment), I never have these problems. I think that you get more realistic cross-channel signal strengths as well. Aside from cost, I think sometimes people will use a 6nm OIII to try and get more OIII faster, but since its a narrow band emission it doesn't really work that way. So aside from maybe some cost savings, the consequence of mismatched bandpasses is different star sizes and intensities, that may not realistically reflect the actual differences in intensity across nb channels. 

 

So, I'd get the same bandpass for all channels. IMO, it simplifies and improves NB imaging. 


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#21 rockstarbill

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Posted 25 June 2022 - 03:40 AM

So, I'd get the same bandpass for all channels. IMO, it simplifies and improves NB imaging. 

Completely agree.

 

I tested 3nm Chroma and AD NB filters at f3.3 and it was a lot of noise and very little signal. 




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