The Best DSO Filters

[Vortexical]

Hi all,

I've been using a SkyWatcher 200P 8" with 1.25" eyepieces on an EQ5 mount for a few months now and it's a great first scope. I'm looking now at getting a few extra bits and pieces for it and was looking for some advice on DSO filters. I've already got a selection for planetary and lunar viewing which are great to alter or improve the visual image. If I'm being entirely honest, I've always been ever so slightly underwhelmed by the appearance of many DSO and was hoping anybody with experience could give me an idea of some good purchases to make.

I know that the filters required would be different depending on exactly what I'm looking at, so I'm keen to get any opinions against a full range of targets. Whether it be galaxies, differing types of nebula or clusters, I'd love to know which 3 or 4 filters people never leave home without. I'm based in a fairly typically quiet North Hertfordshire town so there is some light pollution but I've never noticed it as a big issue after twilight - so I'd love to know how necessary light pollution filters themselves might be.

Thanks in advance as always for your trusted opinions!

ja

[Oily]

I've bought a Castell UHC filter after reading all of the reviews but to be honest haven't used it much since taking up AP

[Scott]

not sure if this'll be of help of not

http://www.cloudynights.com/item.php?item_id=1520#top

[Andy_E]

It depends which DSOs you're after. UHC and OIII filters can help with emission and some reflection nebulae (there's loads in the summer sky right now!), but wont offer any help on globular clusters, open clusters or galaxies. As for which is best often comes down to viewing on the night; sometimes I reap better rewards with the OIII and others with the UHC... opinion is often split. If I had to pick just one, I'd say that the UHC gets more use but it's a tough call... some objects just respond better to one filter or the other. Having said that, when used on appropriate targets, both filters will show at least some improvement over an unfiltered view. As for filters to help out with GCs, OCs and galaxies, I would be surprised if there is genuinely any product on the market that can genuinely improve your views. I don't have any first hand experience with LP filters, but most reports tend to report that although some LP is indeed filtered out, the object itself is also dimmed... sounds a bit like six of one half a dozen of the other to me. Unfortunately there is no substitute for dark skies (we've all heard it a thousand times before I know!)

[John]

.... Unfortunately there is no substitute for dark skies (we've all heard it a thousand times before I know!)....

1001 times now - it's absolutely true

UHC and O-III make a substantial difference to some nebulae, notably planetary nebulae and supernova remnants but dark skies benefit all DSO's.

I now just carry one narrowband filter, the Astronomik O-III which is pricey but very good at what it does.

[Andrew*]

As for filters to help out with GCs, OCs and galaxies, I would be surprised if there is genuinely any product on the market that can genuinely improve your views. I don't have any first hand experience with LP filters, but most reports tend to report that although some LP is indeed filtered out, the object itself is also dimmed... sounds a bit like six of one half a dozen of the other to me. Unfortunately there is no substitute for dark skies (we've all heard it a thousand times before I know!)

You're absolutely right, but I wouldn't say the right filters in the right conditions can't make a difference. Under cities still strongly lit with sodium vapour lighting, a good LPR filter can make small increases in the contrast of continuum objects. You will lose some of the good light, but more of the bad light. I don't actually bother using one and rather tend to pick objects that suit the conditions

Galaxies under dark skies come alive. Galaxies under poor skies will never compete, regardless of equipment.

[scarp15]

Dark skies and a good OIII filter - 1002 times

[Stargazer_00]

The Baader Moon and Skyglow filter does help reduce the sickly orange glow of the urban environment. As much as there is no substitute for dark skies we are not all blessed with them and to get out regularily many/most of us have to suffer with light pollution.

This filter is really only useful at lower magnifications when the background brightness increases as the exit pupil size increases, there is neglibable to no real difference at higher magnifications.

If you hold the filter over your eye (lowest possible magnification, 1x!) and look at the sky with both eyes you can see the maximum effect this filter can have, essentially at 1x it entirely replaces orange for a more pleasing, dim blue hue. This makes it easier for pick out DSOs for me. The effect becomes lessend the more you increase the magnification so the effect in a scope at 30x for instance won't be as good as 1x so you may notice some orange there still.

Never bothered using it on the moon. I figure if I'm going to look at the moon then why bother with a filter. It'll rob your dark apdated eyesight anyway so go for the full effect like a man! besides being blind in one eye compared to the other as a result of moon glare is amusing

For nebula, as others say, UHC and O-III are good. Start with a UHC as it's more versatile than a O-III in an 8". An O-III is far more agressive and lends itself better to larger apertures.

[ronin]

Read something on CN that basically said get an O-III and that is the most useful.

Cannot agree or disagree as I don't have any.

Have a simple approach of point scope, look.

[Andrew*]

For nebula, as others say, UHC and O-III are good. Start with a UHC as it's more versatile than a O-III in an 8". An O-III is far more agressive and lends itself better to larger apertures.

OIII filters work well in any aperture, from the 7mm Naked Eye, to 60mm refractorrs, to big dobs. I have seen the veil nebula in a 66mm refractor with one.

UHC filters are more versatile on targets, but OIII filters usually give a more striking improvement on the right target.

Andrew

[Rustysplit]

Another vote for the O-III. The Veil complex, Crescent and Dumbbell nebulae are superb when using one.

[swamp thing]

It depends which DSOs you're after. UHC and OIII filters can help with emission and some reflection nebulae

They will only work on the reflection nebulae that are reflecting emission line stars. Other reflection nebulae they will have no effect on, and in fact could make them worse.

They will obviously help on emission nebulae. Having a dramatic effect on some.

They can also help on some extragalactic nebulae in other galaxies, but not thegalaxy itself.

[AndyWB]

I don't know if it's relevant, but at the beginning of the month I had a look at the Veil nebula from a dark location - both the Eastern and Western parts were visible in my 130mm without a filter. However, a UHC filter did bring out more definition, more shape to both parts. It was impressive.

Monday night I noticed how unusually clear it was here in town, and tried for it again. With the UHC filter I could just barely make out the location of the eastern part. Western part not visible at all. This was not impressive! It was interesting, 'cos the light pollution actually seemed much better than normal.

So, I'd say dark skies beat a filter, but dark skies and a filter can be better still.

[swamp thing]

1376597981' post='2016581']

So, I'd say dark skies beat a filter, but dark skies and a filter can be better still.

That's about the sum of it Andy.

As has been said many times. Nothing will improve your views more than a dark sky.

[YKSE]

Here's one of the most comprehensive filter comparison I've read:

http://www.prairieastronomyclub.org/resources/by-dave-knisely/filter-performance-comparisons-for-some-common-nebulae/

My conclusion is that UHC and OIII are the ones to begin with, and I'm quite happy about my filters, as the performance on veil nebula in my 130P are just as Dave described in the comparison.

[LukeSkywatcher]

And for those of us who cant/dont/wont drive to dark sky locations.................both the UHC and OIII filters will and do improve the views. I say buy both,but be prepared to use the UHC filter more than the OIII,as there are more targets out there that benefit from it.

[Andy_E]

They can also help on some extragalactic nebulae in other galaxies, but not thegalaxy itself.

Do you know I've never thought about that! Looks like Andromeda is going to have a thorough going over with the UHC!

[RikM]

I use both an Astronomik UHC and a SkyWatcher Oiii. Of these two I find the UHC more useful. I am not sure if that's because Astronomik is better than SkyWatcher or because I am using 1.25" eyepieces with medium to medium-low power rather than a 2" true low-power eyepiece, so the high transmission of the UHC gives a brighter image (which I prefer). I also suffer from some light pollution, so I can't get my eyes properly dark adapted; something else that may have me favouring the UHC.

[estwing]

I've just bought the Astronomik UHC second-hand so really lookin forward to using it.

[Andyj]

Here's one of the most comprehensive filter comparison I've read:

http://www.prairieas...common-nebulae/

My conclusion is that UHC and OIII are the ones to begin with, and I'm quite happy about my filters, as the performance on veil nebula in my 130P are just as Dave described in the comparison.

Some very interesting reading at that link. Thanks for sharing. The author has clearly worked hard to give his findings and It has definitely modified my current thoughts as well as dispelling a myth or two. Very informative.

[John]

I've just bought the Astronomik UHC second-hand so really lookin forward to using it.

They are very nice filters Calvin. I thought my Astronomik O-III was expensive when I bought it (used) but it's worth every penny when I use it. It's the only narrowband filter I seem to need and works well in all my scopes

[estwing]

thanks John...anybody seen M42?...now where did he go?

[Stargazer_00]

waiting, waiting, waiting. looking forward to breaking my 14" in on M42 really badly I bet you are too for your 18"

[estwing]

seven sisters first...m42 gonna get a dark sky treatment for the wow..

[John]

Personally I get the biggest "wow" in viewing objects where the filter makes a massive difference such as the Veil or Owl nebulae. I don't use it much on the brighter ones such as M57, M42, M27 etc as I prefer the unfiltered views of those objects.

The "wow" comes for me when adding the filter enables you to see something that was previously not, or was hardly visible