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Filter advice for imaging ?


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I am currently using Baader 36mm unmounted filters, LRGB and the Ultra NB Ha, OII and SII.

To me they seem fine, only thing I would say I am a but disappointed with is the very bright stars produce Halos for OIII.

But its like anything these are pretty much all I have used so how do I know I am not missing out on getting better data.

Now I am sure the Astrodons are better, they must be to get the praise they do and to command the price, but if I were to treat myself, am I going to see a significant difference or a very slight difference ?
Also, if things do improve  is it just the NB filters that will improve or do the LRGB also give significant improvements, as these are around £800 a set on there own.

Steve

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The difference between my Baader (7nm??) and my Astrodon 3nm NB filters is huge and I mean huge, LRGB less so. With that said there is now much more competition in ultra-narrow filters than when I bought mine, including some from Baader.

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1 hour ago, wuthton said:

The difference between my Baader (7nm??) and my Astrodon 3nm NB filters is huge and I mean huge, LRGB less so. With that said there is now much more competition in ultra-narrow filters than when I bought mine, including some from Baader.

Cheers, they the ultra NB ones I have 3.5 and 4.5 Nm so not as narrow band as the Astrodons, and I thought they were expensive but nowhere the Astrodons. 

When I finally took the plunge to lay out £1K for all the Baaders they then released their CMOS optimised ones and the ones I got seemed to have been withdrawn so I maybe lost out there as well.

Steve

Edited by teoria_del_big_bang
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I didn't seem to get much response when I first asked about whether Astrodons were worth the money but now changed title as my question is more findemental.

My current set of filters are all Baader (LRGB and ultra NB Ha, OIII & SII).
Generally I am happy with results, although having said that I really no nothing else so not sure how much better my data may be with Astrodons, or Chroma (or others I am unaware about).
One thing that I am not happy with it the large halos I get on OII on the brighter stars. And I did not think originally I did get such halos, but maybe I just imaged targets with dimmer stars to begin with.

Astrodons always have seemed to be the ultimate in NB for sure (not sure how much improvement on LRGB there would be)  since I took up the hobby and then Chroma seemed to be a near rival and at one time a cheaper option but they now seem to be pretty much on a par price wise, but are they on a par functionality wise ??

So money no object I would just get some new filters and maybe ask if Astrodon or Chroma (or some other) would be the best choice and buy all new, NB and BB.
But I am not really on a position to just find £3K at the drop of a hat.
Alternatives is to replace my OII for now which hopefully would cure the halos and give me a chance to see what improvements to data collection it gives me over the Baader ultra NB, and then maybe upgrade bit by bit.
Issue this gives me is I then have a non parfocal filter as Baaders are 2mm and Astrodon & Chroma 2mm. So I would have to at leas offset the focusser or re-focus each change of filter type, also in theory my BF will be out for the new filter albeit 0nly 0.03 mm so probably not that noticeable.

  My other thought I had is that in my flattener I have permanently fitted a IDAS P2 Light Pollution Suppression Filter, really to help with LP when using the LRGB filters but wondered if that could cause so reflections to cause the halos, I very much doubt it but wondered to remove it and try on same target as I get the halos next session. Also even though I know the OIII is the correct way round whether just to try turn it round ???

So just seeking advice really,

  • is the difference in thickness a big issue if I don't replace all filters ?
  • If I do change which should I go for Astrodons, Chroma (Or other) ?
  • Any thoughts on the LP filter permanently in the flattener ?
  • Should I try turning the Baader OIII round (currently correct way round according to the arrows on the side) ?

Steve

Edited by teoria_del_big_bang
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I really am struggling for help here folks.
I need to fix my OIII halo issue but ideally do not want to spend £3K doing so, but if thats the only sure option to have the best NB imaging then maybe I have to.

  • If I do replace my filters, or some of them, then it will be Chroma or Astrodon (If I can get hold of any at the moment ?)
  • If I just replace the OIII it will be thicker than the Baaders and so will need focussing everytime I change from OIII to to OIII.
  • I really do not want to focus everytime I change filters as with the clouds up North I usually loop my sequences, so do not say do 10 x Ha, then 10X OII and then 10 X SII I usually do one frame of each then loop round the 3 filters so I would be focussing nearly every image.
  • So next option is to just buy 3 new NB filters and leave my LRGB. Not ideal but at least reduces the refocussing as often sessions will be LRGB or NB only, sometimes I do Ha with RGB but would have to cope with that.
  • I can always upgrade the LRGB later but not even sure if imaging wise I gain anything apart form removing the need to refocus sometimes.
  • I am assuming that the difference required in BF would not really matter as it is only 0.3 mm difference.

To reduce the cost a little I could get 5Nm instead of the 3Nm but with Bortle 4 (ish) am I loosing anything using 5 Nm over 3 Nm. I know the bandwidth of the 3 are just narrower but what difference would I see in my data, is the improvement just at near full moon.

Steve

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Just one thing is you can set filter offsets with NINA so you won't need to focus on every filter change so that should be a non issue for you.

How about Antlia filters, supposedly very good and a bit cheaper than Astrodon or Chroma? Not used them (yet) myself......

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Yes exactly that or there is a plugin called "Dark's Customs" which can do it for you.

 

When done don't forget to remove any "Focus after Filter change" you may have in your sequences.... Ask me how I noticed that 🙂

Edited by scotty38
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Swapping filters between subs strikes me as a little pointless in narrowband, but I may be missing something?  I can see why you'd do it in R,G and B because you need about the same number of each and being short on one is useless. More would always be nice but slightly too few, provided you have the same number of each, can give you an image.

It's different in NB. You are always going to need a lot and you don't need the same number of each, so shooting one set then another makes sense. It makes even more sense if you use somewhat moonlit nights for the Ha.

Do you need the same make of Ha and OIII? Depends on what you're going to do with the subs. If you're going to add the data to (L)RGB then you don't. The main difference will be in star size and you won't be including the stars in the LRGB data.  If your project is NB-only then I guess you really do need the same filters to get a good match on the stars.

Astrodon NB filters are stunning, as they should be. I've processed their RGB data as well and, quite honestly, I don't think it's that different from Baader data. So... fancy NB filters, yes. Fancy LRGB, not so important.

Olly

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48 minutes ago, ollypenrice said:

Swapping filters between subs strikes me as a little pointless in narrowband, but I may be missing something?  I can see why you'd do it in R,G and B because you need about the same number of each and being short on one is useless. More would always be nice but slightly too few, provided you have the same number of each, can give you an image.
It's different in NB. You are always going to need a lot and you don't need the same number of each, so shooting one set then another makes sense. It makes even more sense if you use somewhat moonlit nights for the Ha.

I think it's me that's missing something Olly, and that's experience. I was treating NB just like BB but what you say does make a lot of sense to me now.
I think in the past I just wanted to get some data to work with , and where I am in UK it can be weeks before another clear night occurs, and often the target has gone before I get chance to get the next filter done, but maybe, unless I move somewhere with less cloud, I just have to be patient and gather the data when I can and if that ends up being next year, so be it 🙂 

48 minutes ago, ollypenrice said:

Do you need the same make of Ha and OIII? Depends on what you're going to do with the subs. If you're going to add the data to (L)RGB then you don't. The main difference will be in star size and you won't be including the stars in the LRGB data.  If your project is NB-only then I guess you really do need the same filters to get a good match on the stars.

Good point I had not thought about.

48 minutes ago, ollypenrice said:

Astrodon NB filters are stunning, as they should be. I've processed their RGB data as well and, quite honestly, I don't think it's that different from Baader data. So... fancy NB filters, yes. Fancy LRGB, not so important.

Stunning if you can get hold of them 🙂 
Not having to get LRGB will save some cash, cheers Olly

 

Many thanks Olly, just the sort of help I was needing 🙂 

Steve

Edited by teoria_del_big_bang
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For what it's worth, I replaced my Baader Oiii with an Astrodon, while keeping my Baader filters for everything else. I find this gives me star sizes that match quite nicely in narrowband, since they don't bloat as much in Oiii as they did with the Baader filter. Yes, I have to refocus but that's not a major problem for me since the NB runs are typically long.

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4 minutes ago, Shibby said:

For what it's worth, I replaced my Baader Oiii with an Astrodon, while keeping my Baader filters for everything else. I find this gives me star sizes that match quite nicely in narrowband, since they don't bloat as much in Oiii as they did with the Baader filter. Yes, I have to refocus but that's not a major problem for me since the NB runs are typically long.

Thanks, thats actually worth a lot, good information to have 🙂 
Now the issue is getting hold of a 36mm unmounted OIII Astrodon. I guess I just have to order and wait, I even tried the official outlet of Astrodon in US and they have everything but the OIII in 36mm.

Did you get the 5NM or 3NM ?

Steve

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Well.... I've ordered my mono camera, well my wife has for my 60th... and after much reading I think I'm going Chroma with 5nm Ha and 3nm Oiii and Sii. The rationale on the 5nm is that it captures the Nii that 3nm doesn't and 3 vs 5 is neither here nor there for Ha if the moon is up. That's what I'm told and holds up from what I've read too.

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