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Stargazing Nebula filters

  1. Jul 24, 2016 #26


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    then if you have a really big scope you can start getting this sort of detail
    including the granularisation. That I would like to be able to do haha

  2. Jul 24, 2016 #27


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  3. Apr 26, 2018 #28
    Hello stargazers, I'd like to revive the topic about nebula filters, more particularly I am interested in UHC filters for observing planetary nebulas. I have read lot of discussions, reviews and opinions on this topic over internet, but it would be very interesting to get some feedback from PF "stargazing" community :)

    I wonder whether:
    1) do you use any UHC filter (or other narrowband filter) for nebula observations? If yes, which one?
    2) what are your light-pollution conditions at your place?
    3) what telescope aperture do yo have?
    4) what would be your subjective comparison of the view with or without the filter

    On my side:
    1) So far I would probably buy something like Orion Ultrablock, nothing more expensive like Lumicon UHC
    2) According to light pollution map, my place is class 4 in Bortle scale.
    3) I've got 8" dobsonian
    4) never tried one...

    Sorry if this post looks like questionnaire, but I thought it could be interesting for all stargazers, not only me :)

    Thanks for your replies
  4. Apr 26, 2018 #29


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    From what I have read, I would think that most seasoned visual astronomers will have tried many different kinds of nebula filter (probably a drawer full of discarded ones) and spent a lot of money. 'The one you just ordered' will always be the answer to the maiden's prayer - maybe until you actually look through it - but ambient conditions differ from site to site, especially in town.
    I reckon the only filters that really do what they are supposed to are the narrow band ones which are (necessarily) only for long exposure astrophotogtraphs.
  5. Apr 26, 2018 #30


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    I have a light pollution filter that I sometimes use. It seems to help somewhat, depending on local conditions. But it's not a significant difference. You'll probably get the best results if you're looking at emissions nebulas through somewhat narrowband filters since you can block out most of the light except for the emission bands you want to see. Unfortunately I don't have any narrowband filters designed for visual use, I only have them for my camera.
  6. Apr 26, 2018 #31
    1. I used pretty much all of the visual narrow-band nebula filters. Which one works the best depends on what wavelengths the nebula emits, overall UHC and OIII are the best but if the nebula is mostly emitting H-alpha and H-Beta a OIII filter.
    2. It was pretty good (similar to your I expect or slightly better especially at some star parties at darker locations) but then I moved and mostly stopped doing astronomy.
    3. I have used nebula filter in telescopes from 9 to 60 cm. Most of it was with our astronomy clubs F/4 45 cm Newton and 38 cm Dobson.
    4. That is one of those question that depends on a myriad of variables. Sometimes better, sometimes worse. Almost always different. Magnification and exit pupil might change the result. So will the nebula surface brightness and if there are variations in which emissions dominate in different parts of the nebula. For instance the Dumbell nebula can look very different depending on which filter you use (and different from using no filter).
  7. Apr 26, 2018 #32
    yes I agree, it is quite easy to give in temptation when you are enthusiastic amateur :) It is almost one year since I am reconsidering the purchase of the filter because I really don't want to spend my money for something what I would keep unused in a drawer. Maybe I reconsider too much ...
  8. Apr 26, 2018 #33
    Initially I was thinking about this category of broadband filters (LPR). They are not so expensive and theoretically they could be used for more deep-sky objects. But looking at the transmission graphs, majority of them seems too broad, maybe not that helpful in a suburb area.
    I agree, it seems that narrowband filter should be more efficient for emission nebulas (planetary nebulas and HII regions are of my interest)
  9. Apr 27, 2018 #34

    Oh, that doesn't sounds good you had to stop doing astronomy, is the light pollution so bad at your current place?

    Honestly, I am bit afraid to jump directly to OIII filter, isn't it too much specialized? On the other hand, it could better suppress the light pollution... I found this link useful when comparing UHC and OIII filters - the guy was doing test with 4 types of filters on some popular nebulas.

    Regarding the emission lines, it seems there are two groups of UHC filters. All of them transmit Hβ and OIII lines, but regarding Hα, some of the filters block the near-red band (eg. Orion Ultrablock) and some of them transmit it, including Hα (Astronomik UHC), comparison here. Do you have experience with both types?

    EDIT: sorry, Lumicon UHC is blocking Hα line
    Last edited: Apr 27, 2018
  10. Apr 27, 2018 #35

    Andy Resnick

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    For me:

    1) No.
    2) Awful: urban conditions.
    3) 5.5" refractor (400mm/2.8 telephoto lens)
    4) N/A.
  11. Apr 27, 2018 #36
    No, actually the sky is better here, there is no 2.5 million population city 70 km away and there are three nearby (30 km) areas with dark skies instead of two. The local astronomy club however has no dark site observatory. I'm in Sweden and I don't fancy being alone on a deserted forestry road in the middle of the night in -30C with no heat or power setting everything up from scratch every time. The lack of company then makes it very hard to become motivated to observe or do astrophotography. I still do some astronomy especially in autumn and I go to star parties.

    I'd get the UHC before the OIII for the same reason you stated.

    Hα is almost exclusively useful only for photography, it's a much stronger emission line compared to Hβ but our eyes are very bad at detecting Hα. I don't know if I have looked through a UHC with Hα transmission but I _have_ looked through a photographic Hα filter and at that was useless on everything.

    Not to chase you away but have you tried https://stargazerslounge.com/ ? It's a very active and friendly amateur astronomy forum and there is a huge number of threads there already about filters.
    Last edited: Apr 27, 2018
  12. Apr 27, 2018 #37


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    completely agree ... great forum. joined up there late last year several months after I got into solar Ha observing and imaging.
    Most of my posts are in the solar sections of the forums

  13. Apr 28, 2018 #38
    oh, those are really tough conditions!

    ok, it seems that UHC filters blocking the red band should do better job during visual observations.

    I visited and read discussions on several similar forums, but I probably missed this one, I'll check it - thanks for the hint. But anyway, I was interested in the opinions of community over here on PF, and I am glad that I could get it - thank you all for your feedback!
  14. Apr 28, 2018 #39


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    That's the truth! Even working in ones back garden can get stressful when things start to go wrong. The brain works a lot better with another one nearby to bounce ideas off. I imagine your forest roads may not have a good internet signal either.
  15. Jul 4, 2018 #40
    In case someone is interested, here is a brief review of my new UHC filter (orion ultrablock). It took me some time to try it, because I didn't have a lot opportunities for stargazing last weeks, but yesterday I manage it finally.
    Although it provided only just slightly better contrast in case of ring nebula (M57), in case of dumbbell (M76) not only contrast was better, but I could see the nebula bit larger as the outer areas that were unseen before, emerged.
    When I checked the HII regions in Sagittarius, the improvement with filter was even better. Without the filter, I could barely see any nebulosity of lagoon (M8) or eagle nebula (M16), only the star clusters. With the filter, the nebulae emerged and could be seen very nicely. Swan nebula (M17) showed details which I haven't seen before without the filter.
    Saying shortly, I don't regret the purchase and I am happy with the filter - it makes a difference under my area (suburban) conditions.
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