Difference between different (brands) UHC filters

[Exalerion]

Hello everyone!

I'm buying my first telescope, a Skywatcher Skyliner 8" dob, and I'm thinking of buying a 1.25" UHC filter with it to get improved views of all kinds of nebulae. The shop where I'm buying has the following UHC filters to choose from:

• Explore Scientific UHC Filter (€ 51)
• Optolong Premium UHC Filter (€ 52)
• Omegon UHC Filter (€ 58)
• Astronomik UHC-E Filter (€ 64)
• Baader UHC-S Filter (€ 79)
• Astronomik UHC Filter (€ 95)
• Lumicon UHC Filter (€ 193)

They also have some other filters which are not categorized as UHC filters, but I think should be:

• Skywatcher Deepsky Filter (€ 52)
• Orion SkyGlow Broadband Filter (€ 79) -> more Light Pollution (LP) than UHC I guess
• Orion UltraBlock Narrowband Filter (€ 99)
• Thousand Oaks LP-1 and LP-2 Broadband and Narrowband Nebula Filters (€ 105) -> again Broadband probably more for LP I guess
• Lumicon Deepsky Filter (€ 193)

I'd rather not spend 193 euros on the Lumicons (although I've read good reviews about those), but which one is the best one apart from the Lumicons? I've been searching a lot on Google for threads about this and UHC filters seem to be the best allrounder, but every time different filter brands and types are discussed and I just can't make up my mind with all the information out there. I know there are broadband and narrowband (true?) UHC filters, but I guess most of the ones I listed are broadband? I've also read that broadband filters (which are more for LP than UHC I think) and especially Light Pollution filters aren't really that effective at all, especially compared to narrowband...

Or should I not be buying a UHC Filter for a first telescope in the first place, and just get used to the unfiltered views lol? I believe my night sky light pollution level is around level 6 to 7 (Bortle scale).

If someone has some personal experience here with one or more of these filters, your opinion would be very much appreciated :-)

[Charic]

I can tell you that you have bought a reasonable scope and if its truly  your first, and depending on your locality and seeing conditions it could well be your last? until you have the desire to get a larger aperture in order to see more!

At present, I don't use any filters, and I'll assume the decision to buy one is similar to purchasing an eyepiece ? The fact that you will only know if its the right one, after you have bought one and tested it for yourself.

The one that works will be sufficient, and will not necessarily be the most expensive one, as in my case with my choices in the eyepiece department.
Against some well respected brand names, some very expensive, Im more than happy with the results obtained so-far.

If your seeing conditions allow, I'm sure there will be a suitable UHC that will most suit your needs. Hopefully folk here,  having used them on the same scope will be better  equipped to advise you, but its your decision in the end.

You mention in your last few words your estimated Bortle scale, getting your scope to a darker site will work wonders.

Welcome to the SGL.

 

[Stu]

The 8" is a very decent scope and should give you lovely views for years to come.

I don't see any reason to hold off buying a UHC filter if you want one. Out of those listed, I would probably go for the Astonomik UHC at 95 euros. I have not used one (I have Lumicon) but have read enough reviews from people I respect to know they are good!

Of the others, I used to have an Orion Ultrablock which was very useful too. I would probably not both with the other broadband filters, but I would consider an OIII once you have started using your scope more, great for objects like the Veil as well as plenty of others.

[ronin]

I tend to refer to this for the filter characteristics: http://www.astrosurf.com/buil/filters/curves.htm

Someone on CN did an actual measurement of filters, 4 or 5 of them, but I think it wa OIII's that they measured. Interesting results as one of them just about missed all the OIII wavelength.

UHC's seem to fall into 2 types. One is a sort of bit wider OIII as in OIII+Hb, the other seems to be OIII+Ha so 2 distinct bands at opposite ends of the visible spectrum.

So far I have never used a filter, maybe I had better get one to try one day. So cannot make comment of which or how I find any specific item. May be worth looking up Dave Kinsley (??) artical on which filter he found good/bad on which object. Will say that I read it and he used a UHC filter that resembled an OIII filter in type so as half expected the 2 filters usually gave similar results. Did seem a little odd that he did not include an Ha filter in the comparison.

[Dave In Vermont]

To your question: With an 8" aperture/light-gathering, I'd suggest the Astronomik UHC. The Astronomik UHC-E is, by accounts I've been hearing overhere, excellentif you have a smaller scope. But 8" will certainly handle a UHC. The other one that I'd recommend is an OLDER Lumicon UHC. But an OLDER one only. Lumicon was recently sold and, according to all I've heard (I'm a 'Filter-Nut' and have been following this closely) - their new ones are just plain "weird." If you can find verifiable OLD stock Lumicons - toss-a-coin between Astronomik and Lumicon. Perhaps both!

My 2¢,

Dave

[TareqPhoto]

To be honest, i was planning to buy Astronomik UHC filter, but i saw SkyWatcher very cheap UHC and i know that i will buy narrowbanding filters in the future so i didn't want to waste big money or even slightly little more on a filter that i won't use later for sure, so i decided o that SW to save little budget and give a try, still didn't use it but i won't give it a big deal if it didn't work good for me, i will buy an astro camera later and give it a try.

[Exalerion]

Thanks a lot for your input guys!

13 hours ago, Stu said:

Out of those listed, I would probably go for the Astonomik UHC at 95 euros. Of the others, I used to have an Orion Ultrablock which was very useful too.

12 hours ago, Dave In Vermont said:

To your question: With an 8" aperture/light-gathering, I'd suggest the Astronomik UHC.

I've read good reviews for the Astronomik UHC as well, but I've also read that it is pretty broadband for a narrowband UHC filter?

Also, is the Orion UltraBlock Narrowband better than the Astronomik UHC filter?

12 hours ago, Dave In Vermont said:

The other one that I'd recommend is an OLDER Lumicon UHC. But an OLDER one only. Lumicon was recently sold and, according to all I've heard (I'm a 'Filter-Nut' and have been following this closely) - their new ones are just plain "weird." If you can find verifiable OLD stock Lumicons - toss-a-coin between Astronomik and Lumicon. Perhaps both!

Well, how do I know if it's the OLDER Lumicon UHC filter, instead of the new one? The description says "The original Lumicon 1.25" Ultra High Contrast Filter... etc.", but I don't know if that means it is the older one. But €193 is way over my budget for a UHC filter anyway, €100 would be the max.

 

I'm still not convinced to buy any UHC filter anyway with my very first telescope.. Is it really that great of an addition? I really do want to view nebulae though.

I could also buy a good 1.25" FE or Barlow lens like the Explore Scientific 2X Focal Extender, or the TeleVue 2X Barlow (not the Powermate, too much €) to double my magnification range. Any thoughts on that as well?

[John]

A good UHC filter is very worthwhile if you are interested in viewing nebulae and in particular planetary nebulae and super nova remnants. The UHC and O-III filters can make a really noticable difference on such objects.

If these objects are not of much interest then don't buy a UHC filter.

Of the lower cost ones, the Explore Scientific UHC seems to have decent specifications.

 

[Stu]

I understand that the Astronomik is a little more generous in bamdpass that Lumicon for instance, but, without trying to repeat myself, a number of very experienced observers on SGL are quite happy with them.

Some filter curves for you. It is a balance of cut off of unwanted frequencies as well as the percentage of transmission for the target frequencies.

Here are some more graphs. The UltraBlock seems to have a decently narrow bandpass but the transmission appears lower than others, particularly the Lumicon.

Don't over think it though, if you don't want to spend the cash, buy a cheaper one for now and see how you get on with it.

[John]

On the Astronomik filters, the O-III Astronomik is known to be "more generous" than the Lumicon and a number of other brands but it's still a great O-III filter in my opinion.

I believe the Astronomik UHC is more in line with other brands on it's band pass width. The Orion Ultrablock is pretty good but I'd pick an Astronomik UHC over it given the choice. The whole production quality of the Astronomik's is a notch better than the Ultrablocks in my view.

 

 

[Stu]

Oops, I posted about the OIII not the UHC Astronomik. Doh!

Will dig out the right info.

EDIT To be fair to myself, the UltraBlock is more like an OIII than a UHC, that's why I posted the graph including Lumicon OIII

[Exalerion]

Thanks for the graphs Stu! I'm indeed not really looking for O-III filters, just narrowband UHC filters since they seem to be more all round and don't filter out the H-Beta lines, and sometimes also not the H-Alfa lines. I guess I'd want all 3 lines since that would be the best all round option (again, I'm just a beginner and I can always buy additional filters in the future if the need is there). Broadbands seem to include Ha more often while narrowbands don't, right?

1 hour ago, John said:

Of the lower cost ones, the Explore Scientific UHC seems to have decent specifications.

So the Astronomik UHC seems to be a good choice, but it also costs about €40 more than the other cheaper ones, being the ES, Optolong and Omegon UHC's. Anyone have experience or some thoughts on those? John says the ES one has decent specs, but do the Optolong and Omegon not have decent specs? The graphs I find all tend to look very similar lol.. Someone from AST Optics (where I'm buying) recommended the Optolong as he had good experiences with it.

[John]

They could all be the same filter - re-branding is widespread amongst astro equipment apart from the top line stuff. Example: the Celestron O-III is exactly the same filter as the Baader O-III.

H-Beta is much more limited in the potential targets for for the committed deep sky enthusiast. H-Alpha is not visible to our eyes so is an imaging or specialist solar filter as I understand it.

Personally I'd get an Astronomik O-III and use that as my sole deep sky filter. In fact I did for a few years with scopes from 4" to 12" in aperture

 

 

[Exalerion]

Hmm, well I've found this old thread and I think that it really is useful to start with a UHC filter first, as H-Beta isn't really that limited as Don Pensack explained. I just like the idea to have some more options and to not be limited to O-III only. In my view, narrowband UHC's are designed to pick up H-Beta and O-III, and that's exactly what I want. I could wait a while and save some more money for the Lumicon UHC, but the Thousand Oaks LP-2 seems to be legit as well, being a bit more narrowband than the Astronomik and a pretty good equivalent to the Astronomik but especially the Lumicon if I understand it correctly. Any thoughts?

[John]

How about an Omega DGM NBP filter ?. Excellent UHC type and preferred (slightly) by David Knisely over the Lumicon UHC:

http://okularum.eu/index.php?route=product/product&product_id=50

This also throws up the 1.25" vs 2" issue I guess. If you get 2" eyepieces you will want the filters to fit them .......

[alanjgreen]

You get what you pay for with filters. Either get the astronomik as a lifetime purchase or buy a cheaper one as a stop gap while you save for the more expensive. Don't feel bad about buying an expensive filter, they last for years. Get 2nd hand if price is a concern?

i had a skywatcher UHC and it gave good service on my c8 and c11. 

eventually moved to astronomik and now I do not need to buy again.

the skywatcher was okay and gave good views of the big uhc nebulas. The astronomik offers a good improvement on both the amount of nebulousity seen and just as importantly on the star light of the field stars giving a more pleasing and recognisable view.

If I were a beginner then I would buy the skywatcher uhc again as it was a good starting point. Do not get the skywatcher o3 as it is not very good and lets very little light through giving a poor field and unrecognisable view. 

Alan

[GavStar]

I think filter choice is more dependent on individual preference than many other Astro equipment. I read lots about filters on the net including David Knisely's reviews and so bought a uhc filter (the Dgm npb which is David's favourite filter). However I've hardly used it since I didn't like the effect it had on the stars (I saw ghost images but I know many people don't). I do need to give it another shot.

Then in the pub Stu mentioned to me how good the Veil looked with an oiii filter. This prompted me to purchase a lumicon oiii filter (thankfully an old version as per a previous thread) and the views were fantastic. It was the first time that a filter has really worked for me (thanks Stu!)

I then tried to source a (old version) lumicon uhc filter but had no success. Since there is no way to be sure in advance whether it's a new or old version I actually ordered one from three different European vendors hoping one had new 'old' stock but none did- so all three went back for a refund since the transmissions specs for the new lumicon uhc were not good.

I did further research and in the end ordered a astronomik uhc which had a transmission of 97% and from what I have read both the Astronomik uhc and oiii filters have recently had the bandwidth tightened up so that they are basically the the same as the old lumicon uhc and oiii. I haven't had the chance to compare the astronomik uhc with the dgm npb and lumicon oiii but hope to do this soon. 

So for me (taking account of how personal filters are) I would get the astronomik uhc AND oiii (since seeing the veil with a good oiii is amazing). I also like getting widefield views using uhc and oiii filters so have gone for 2 inch rather than 1.25 inch filters but that is out of your budget. 

[Stu]

5 minutes ago, GavStar said:

Then in the pub Stu mentioned

Ssssshhhhhh! Don't tell them all that's where we meet, they'll all want to come!  

I love my Lumicons! Both UHC and OIII have similarly high transmission levels, great filters.

[Exalerion]

I've indeed read some good things about the DGM NPB filter as well, but they don't really sell these in a lot of large shops around here it seems, and I'm a little bit hesitant when it comes to buying things from random shops not close to where I live lol... But I guess that in the end, the difference between the Astronomik, 1000 Oaks LP-2, (old) Lumicon and DGM NPB isn't very big anyway..?

Thanks a lot for your insight well, Alan and GavStar! I'm indeed leaning towards the Astronomik, or maybe the LP-2. The (old) Lumicon might be the top one, but so is the price lol.. Are there any charts showing the new, tightened up bandwidth of the Astronomik UHC'? Because if the Astronomik ones now (pretty much) equal the Lumicons for half the price, the decision would not be so hard =P Are the Astronomik UHC's on the market right now all new, tightened up ones?

About 2" vs 1.25", I might buy 2" eyepieces in the (not so near) future, but then it would have to be possible to use the 2" filter with both 2" and 1.25" eyepieces. I don't know if I want to focus on 2" right now, also because it's usually twice the price with the higher end UHC filters.

Stu, do you have the "old" or new Lumicons?

[John]

32 minutes ago, GavStar said:

I think filters is more dependent on individual preference than many other Astro equipment. I read lots about filters on the net including my David Knisely's reviews and so bought a uhc filter (the Dgm npb which is David's favourite filter). However I've hardly used it since I didn't like the effect it had on the stars (I saw ghost images but I know many people don't)....

 

I've seen that effect, to varying extents with all the filters I've used Gavin. I've sort of accepted it as a necessary side effect that comes with the multi-layer approach to the application of the filtering coatings that they use in production. The DGM / NBP shows it a little more than the Lumicon O-III but I've seen it much more in other filters ...

Is there a filter that has no effect on star images at all while giving top notch UHC or O-III performance ?. Not sure that I've found one yet

 

[Piero]

1 hour ago, Exalerion said:

I've indeed read some good things about the DGM NPB filter as well, but they don't really sell these in a lot of large shops around here it seems, and I'm a little bit hesitant when it comes to buying things from random shops not close to where I live lol...

 

I got my 2" and 1.25" DGM NPB from okularum.eu (http://okularum.eu/) in Denmark. Their service has always been excellent and Jan is a very good chap.  

[Piero]

1 hour ago, John said:

I've seen that effect, to varying extents with all the filters I've used Gavin. I've sort of accepted it as a necessary side effect that comes with the multi-layer approach to the application of the filtering coatings that they use in production. The DGM / NBP shows it a little more than the Lumicon O-III but I've seen it much more in other filters ...

Is there a filter that has no effect on star images at all while giving top notch UHC or O-III performance ?. Not sure that I've found one yet

I agree with this.

I remember that my Astronomik OIII and UHC added a kind of layer/colour to stars. The fact is that these filters generally add a green colour to stars because they pass the OIII band (which is green in the spectrum). The DGM NPB can show stars as green/red because it passes the narrow band around the h-alpha lines on the red side of the spectrum.

I don't think this issue will be ever solved. If they did, it would mean that such a filter would filter the background sky, but not the stars. Personally, I am not bothered by that effect of these filters on stars. I use filters to highlight nebulae and their features. Stars are just useful check points to know how to orientate.

[GavStar]

21 hours ago, John said:

I've seen that effect, to varying extents with all the filters I've used Gavin. I've sort of accepted it as a necessary side effect that comes with the multi-layer approach to the application of the filtering coatings that they use in production. The DGM / NBP shows it a little more than the Lumicon O-III but I've seen it much more in other filters ...

Is there a filter that has no effect on star images at all while giving top notch UHC or O-III performance ?. Not sure that I've found one yet

 

Yes I can see that it would potentially impact all filters and it's the nebulousity that is key. I just find the impact on star shapes more distracting with my npb than my lumicon oiii.