Astronomik or Lumicon OIII filter

[Stu]

I know there is a fair amount of discussion around OIII filters on the forum, but I wanted to ask a specific question around which if these two would be best in a smaller scope ie a 4" apo triplet. Potentially it would also be used in a 10" newt as well.

I have used a SW OIII with some success before from dark sites on the Veil and NA Nebulae and am looking to purchase a top quality filter.

I believe I'm right in saying that the Lumicon has the narrower bandpass, so potentially may not be as good in a smaller scope, but it may be that the narrower pass helps cut down LP provided I'm well dark adapted.

Any comments appreciated, including which shows stars in the best way (not that important but interesting to know), and which is most likely to show the nebulae to best effect. I have 31t5 and 21e eyepieces which would make most sense to use with lowest mag and good size exit pupil.

Cheers,

Stu

[alan potts]

Stu,

I have the Astronomik, to use words from an early post today, it came up first secondhand so that made my mind up. I really do not think that there will be anything between these two fine filters. For that matter I am not sure that  you would find a site member that has both but you may find someone  that has used both at some point, not having them side by side is going to be a tough call as to which is best though.

The Astronomik is very good (with the limited use I have given it) in the 115mm and the 70mm, I believe you read my two reports. I get the impression more people have the Astronomik OIII than the Lumicon.

Sorry I can't help more.

[swamp thing]

Hi Stu

I've compared them directly in both my 10" Dob and an observing buddies 120ED. You'd need better eyesight than me to tell them apart.

Of coarse you could always come along to one of the Surrey meets and try for yourself. A couple of the guys have the Astronomik version and I have the Lumicon one.

[Stu]

Stu,

I have the Astronomik, to use words from an early post today, it came up first secondhand so that made my mind up. I really do not think that there will be anything between these two fine filters. For that matter I am not sure that you would find a site member that has both but you may find someone that has used both at some point, not having them side by side is going to be a tough call as to which is best though.

The Astronomik is very good (with the limited use I have given it) in the 115mm and the 70mm, I believe you read my two reports. I get the impression more people have the Astronomik OIII than the Lumicon.

Sorry I can't help more.

Thanks Alan. Somehow I'm leaning towards the Astronomik, don't quite know why though!

[Stu]

Hi Stu

I've compared them directly in both my 10" Dob and an observing buddies 120ED. You'd need better eyesight than me to tell them apart.

Of coarse you could always come along to one of the Surrey meets and try for yourself. A couple of the guys have the Astronomik version and I have the Lumicon one.

That sounds like a very good idea, although it would involve a seemingly impossible series of coincidences such as a clear night when it don't have any commitments etc etc! Will keep an eye on the Forum to see if I can get down to one......that's if I don't just get impatient and order one first!

Cheers,

Stu

[John]

I have an Astronomik O-III too although I'd have happily bought a Lumicon if that had come up first. Both brands have excellent reputations. The Astronomik does seem very effective even in my 4" scope so maybe it's band pass width is a little more generous than some other O-III's.

[swamp thing]

That sounds like a very good idea, although it would involve a seemingly impossible series of coincidences such as a clear night when it don't have any commitments etc etc! Will keep an eye on the Forum to see if I can get down to one......that's if I don't just get impatient and order one first!Cheers,Stu

don't think you'll go far wrong with either anyway matey.

I've actually compared them at two different sites as well, one with moderate LP and at a pretty dark spot too (VLM 6)........still couldn't pick

[rwilkey]

Hi Stu, that's a difficult one as I have only used the Lumicon, which in my 4" doublet works fine.  Yes, it has a narrower bandpass and gives a darker sky blocking many stars out, but like you I had the SW OIII to compare with, which has a much wider bandpass, so came as a bit of a culture shock when I used the Lumicon.  But by all accounts, esp. John's above, I think the Astronomic will be great too.

[alan potts]

Thanks Alan. Somehow I'm leaning towards the Astronomik, don't quite know why though!

Stu,

Strength in numbers.

Alan.

[Joves]

Haven't tried the Lumicon, but have both the Astronomik 1.25" CCD and 2" visual version. Excellent filters. Is there a big price difference between the Lumicon and Astronomik? If so, it sounds as though this could be the governing factor.

[John]

Haven't tried the Lumicon, but have both the Astronomik 1.25" CCD and 2" visual version. Excellent filters. Is there a big price difference between the Lumicon and Astronomik? If so, it sounds as though this could be the governing factor.

They are priced about the same I think - at the high end for filters. 

[Pig]

Hi Stu,

I have the Lumicon 1.25" and it works much better in my 9.25 than it did in my previous 6" scope.

I have not tried the Astronomik so I cannot comment on its performance

[Naemeth]

Pick whichever comes up second hand first. I have the Astronomik for what it's worth .

[Scooot]

I tried to get a lumicon uhc last year before getting an astronomic. I couldn't find anyone who had one in Europe or knew when they would be in stock so I tried lumicon directly. After adding up all the taxes and a ridiculous amount for shipping it just wasn't worth it. Might be different now of course.

[Tiki]

The bandpass width of the Astronomik is about twice that of the Lumicon. If LP is an issue (but not stray light directly entering your eye) then the Lumicon might be better. I regularly use both a Lumicon OIII and UHC in my 4" frac. Interestingly, the Lumicon UHC has a bandpass width only a little wider than the Astronomik OIII and is really an OIII and H-beta combined filter.

Some interesting filter curves here http://www.astrosurf.com/buil/filters/curves.htm#Astronomik .

[Mark at Beaufort]

Hello Stu - I do like the discussion on the merits of Olll filters.

I stated before that I was disappointed with Skywatcher Olll filter which I sold. So for a few years I just used the UHC filter. However, I recently decided to have another go and bought a TS Olll filter second hand. I am pleased with the results mainly because I can still see some stars. I had a great view of the Veil through the 10" Dob.

Like you I still might purchase a better quality filter in time. I notice that the Astronomik 2" is $200 (£122)  in the US and the Lumicon 2" is $240 (£146) whereas in the UK the best price for the Astronomik that I found was £160. I only mention the US because my son lives in the US and visits every year so I might get him to order it for me.

I still hope that we might get to compare various Olll filters at SGL9 because I know that the Castell, TS and Astronomik will be on show. If you get the chance to visit Surrey it will be interesting on your opinion. However, I get the feeling you might have an early 2014 present.

[Stu]

The bandpass width of the Astronomik is about twice that of the Lumicon. If LP is an issue (but not stray light directly entering your eye) then the Lumicon might be better. I regularly use both a Lumicon OIII and UHC in my 4" frac. Interestingly, the Lumicon UHC has a bandpass width only a little wider than the Astronomik OIII and is really an OIII and H-beta combined filter.

Some interesting filter curves here http://www.astrosurf.com/buil/filters/curves.htm#Astronomik .

Thanks Tiki, some interesting graphs there.

I was a little confused by the Lumicon UHC, seems not to have a very good response at the Hb frequency or am I mis-reading the graphs?

Stu

[Stu]

Hello Stu - I do like the discussion on the merits of Olll filters.

I stated before that I was disappointed with Skywatcher Olll filter which I sold. So for a few years I just used the UHC filter. However, I recently decided to have another go and bought a TS Olll filter second hand. I am pleased with the results mainly because I can still see some stars. I had a great view of the Veil through the 10" Dob.

Like you I still might purchase a better quality filter in time. I notice that the Astronomik 2" is $200 (£122) in the US and the Lumicon 2" is $240 (£146) whereas in the UK the best price for the Astronomik that I found was £160. I only mention the US because my son lives in the US and visits every year so I might get him to order it for me.

I still hope that we might get to compare various Olll filters at SGL9 because I know that the Castell, TS and Astronomik will be on show. If you get the chance to visit Surrey it will be interesting on your opinion. However, I get the feeling you might have an early 2014 present.

Thanks Mark. It's certainly an interesting topic with plenty of technicalities to get your head around! I had read your comments on the TS filter, interesting that it seems better than the SW.

From home, I do have a fair amount of glare from street lights which makes it harder to get dark adapted. I'm edging towards the Astronomik for this reason, although I could always chuck a blanket over my head and go for the Lumicon!! ;-)

Will ponder some more, and then take the plunge, probably sooner rather than later. Can use it over the Christmas break then.

Thanks all for the input, very useful as always.

Cheers,

Stu

[Tiki]

I was a little confused by the Lumicon UHC, seems not to have a very good response at the Hb frequency or am I mis-reading the graphs?

Stu

  My lumicon uhc has a 92% pass rate in the H-beta, 95 and 96% in the OIII's. Perhaps you are mis-reading the graphs.

[Stu]

Thanks Tiki.

This was the graph I looked at....

Seems like the response is low at Hb??

Stu

Edit: I was mis-reading it, was looking at the Ha line! All clear now.

[alan potts]

If what Tiki states is correct and he or she seems to know what they are talking about, then would a Lumicon OIII work as a H beta for the horses head? 

Alan

[Stu]

If what Tiki states is correct and he or she seems to know what they are talking about, then would a Lumicon OIII work as a H beta for the horses head?

Alan

Yes, that would seem to be true, although potentially the contrast for the Hb might be lower because it is also letting the OIII through...

[alan potts]

Stu,

Bearing in mind these Lumicon filters are a fair old price then it may well work as a second rate H beta for someone not wanting to shell out the best part of 200 quid if we are talking 2 inch fittings.

Alan.

[Stu]

Just for my fuller understanding, what is the impact of the frequencies around 4000 and above 6500/7000 A? The Astronomik has a slightly wider pass around the OIII lines, but is very flat outside this, with other frequencies only kicking in above 8000A. The Lumicon has a tighter pass at OIII, but has a burst of frequencies around 4 to 4500 and then again kicking in from under 7000A. Do these have any visual impact, what do they represent?

Thanks for any input.

Cheers,

Stu

[John]

If what Tiki states is correct and he or she seems to know what they are talking about, then would a Lumicon OIII work as a H beta for the horses head? 

Alan

UHC filters that have a strong H-Beta band pass have been used to see the Horse Head. The Orion Ultrablock is one example I can think of. It's a rather good UHC-type filter actually and quite a lot less expensive than either the Lumicon or the Astronomik's. David Knisely on "Cloudynights" often recommends the Ultrablock and he really know his filters 

I think a dedicated H-Beta with a high band pass transmission % in that line is the most effective on objects like the HH though, and it seems to be an object where you need to give yourself every advantage you can get.