View Full Version here: : my impressions of my first UHC and O-III filters

21-11-2006, 04:48 PM
well i got home yesterday and found a nice little parcel containing a Baader UHC-S, Baader O-III and celestron 2x omni barlow.

of course it clouded over lastnight so i didnt get a great chance to check them out, i caught a long enough break in the clouds to get a comparison on m42 so i put in my 25mm with the UHC-S and took a peek, and there was a tiny bit more nebulosity than i could remember seeing before.

I started thinking oh crap this isnt a whole lot better until i realised how light it was outside. i took the filter off and it was bad enough that pretty much all i could see were the stars making up orion with a tiny hint of nebulosity.
at this stage i was very impressed. i only have a 6" dob so going by what everyone was saying about the O-III filters (the baader being as far as i know the most narrow band of them) i didnt think the views would be very good at all, but there was m42 against a really dark background.

after slewing around to as much as i could in the course of 5 mins, if not for the hint of colour produced by the UHC-S i probably would have forgotten it was in there. the O-III was a bit more dramatic dimming things down noticably but the view was very pleasing on nebulae and i definately wouldnt be advising anyone with a 6" arpeture agaisnt using an O-III.

final rundown on m42.

UHC-S: gave a really natural view, still resolving all of the stars in the core whilst enhancing the nebula, id be confident to say that i saw more with this filter on a light enough night that i could read the side of the filters than i have on a darker night without it, you could definately leave this filter in whilst hopping around.

O-III: this was the real contrast enhancer, the nebula appeared a lot brighter than the UHC mabee because of the pitch black backdrop but i lost some of the stars at the core, it was a very pleasing view, you probably wouldnt leave this in while hopping around.

in all, the UHC-S would be great even for smaller arpetures than 6"
smaller than 6" though id probably shy away from the O-III even though the nebulae stands out like a sore thumb you will lose the dimmer stars.

so thats my take on these filters,

21-11-2006, 06:13 PM
Thanks for this info. I really found it interesting because I just purchased a Baader UHC-S , but haven't had a chance to try it out yet. I only have a small scope working at present (5" Newt), and the weather....typical. We should all get together and break the rain drought by buying more astro gear.

I did hold the filter up to my eye last night and noticed it virtually knocked out the orange coloured street lights (sodium type) completely, so with your findings I can't wait to try it out.

The Baaders are reasonably priced too, but don't know how they compare with more expensive ones like Lumicon, etc. Maybe an OIII is next....or a DGM NPB, or...

Clear Skies,


21-11-2006, 07:07 PM
no probs, just a bit disappointing that i could only really test them on m42, tonight isnt looking very good either but i'll follow up here when the skies clear up, where abouts are you located? when we get some clear skies your welcome to come check out the O-III


22-11-2006, 07:24 AM
I'm over the eastern suburbs way in Firle. Thanks for the offer. The weather is the same over here :O)
What area are you from,


22-11-2006, 08:53 AM
Just an observation I made at Ballarat at the weekend regarding UHC filters. If I use one at home in the 'burbs, it really makes a difference to Eta Car and the Tarantulla and makes it stand out. However, I tried it at the camp and it appeared to make the image worse. I gather this is because at home, it drops out the sky glow from all the lighting, improving the contrast a lot. If you don't have much light pollution, there isn't much to "drop out" and so you just notice the drop in light from the nebula in general. Of course, the view was much better even with it compared to home. If you do most of your observing from a city, they will make a huge difference and are worth it.

22-11-2006, 09:26 AM
Yes, that makes sense about the use of a UHC in non-polluted skies. Do you know if a similar thing happens with the OIII filter?

A fellow XW admirer.

22-11-2006, 02:30 PM
hm, id say so with the O-III being a more narrow band filter, although ive heard some people say even from dark sites certain filters enhance observing further.

not a cloud in the sky at the moment, hopefully it stays that way tonight.
oh and im in the western burbs @ semaphore park (where the hell is Firle!)


22-11-2006, 06:58 PM
Good stuff Monoxide :thumbsup: Glad you are enjoying your filters.

23-11-2006, 10:05 AM
Hey Tj, Firle is near Payneham and St Morris, btw. It's where you find light pollution abundant. :( Good to hear the filter works well. I'm waiting for the mirror in my bigger scope to come back after being refigured and coated. Until then, I suspect the filter, or most filters for that matter won't be fantastic in smaller aperture scopes, but maybe I'm wrong...wouldn't be the first time.

23-11-2006, 06:36 PM
had a good night observing lastnight, conditions werent fantastic but i persevered, gave the filters as much of a workout as i could.
i have to say if one of my filters disappeared id be replacing it asap.
also i guess i underestimated the value of adding a barlow to your ep collection, got a nice view of saturn to finish the evening, to sum up lastnight in 1 word, id have to refer to borat and say 'sexytime'

23-11-2006, 10:25 PM
well i think i just gave both filters a worst case scenario test, considering where the moon is right at the moment, i slewed to the lagoon neb and all i could see was the cluster, add the UHC-S and suprise, a bit of nebulosity pops into view with the cluster still there as before, put the O-III in and sure most of the cluster disappeared but who cares, your obviously looking to bring out nebulosity with one of these :P i could make out some structure in the nebulosity that just wasnt there without filters. also using my hand as a mask with both filters didnt really change the view dramatically (half of my hand across the front of the OTA)

next victim was the tarantula neb, uhc-s same comments as everything else ive tried it on so far, enhances it nicely without being overkill on the fainter stars.
O-III was pretty dramatic, again brings out more structure in the nebula but dims everything else dramatically. from what ive seen so far the O-III would just be excellent in a large scope whereas the uhc-s is just a great all rounder, keeping the view natural while enhancing nebulosity.

final words on both:

UHC-S, doesnt matter how big or small your scope is id definately look at getting one of these if you havent got one already (i left the filter in while observing 47tuc and didnt notice till i went to change ep's)

O-III, from the structure this is allowing me to see in nebulosity that you just cant make out without a filter id say this would be an incredible filter on a large aperture, id probably recommend that you look through one before buying it (if you have a smaller scope) because it does dim stars down quite a bit, but i dont see that as a problem since it makes you concentrate on the nebula.

having said all that, id miss them both if something happened to them
hopefully this thread helps some others

24-11-2006, 02:41 PM
Really pleased to hear about the UHC-S performing well. From what you say, the OIII is worth having, and sounds like you got yourself some really worthwhile and value for money accessories. Could be next on the agenda. I'm caught between getting the OIII and a DGM NPB though. I believe it's not quite as narrow band, but more so than the UHC-S. If I get one I'll report how it works too.

24-11-2006, 04:36 PM
I got my first ever view of the Helix last night with a UHC filter (Televue bandmate) in an 8" scope. This was from my light polluted backyard and the sky was so hazy I couldn't see the magellanic clouds. I couldn't see any of the nebula without the filter and while it was still faint with the filter, I could see it with direct vision. Looking forward to clearer skies.

24-11-2006, 11:16 PM
From our viewing site, the sky is semi dark to dark and we find that our filters still make a great deal of difference bringing out much more nebulosity than without them.

We have an Astronomik UHC 1.25" & DGM NPB 2" & 1.25".

Although they are mainly used in our 12" Dob, the 1.25" perform very well in the Meade ETX125PE ( 5" ).

Must admit the NPB is used more than the UHC in both scopes as it provides far better views.