OIII Filter

[Solanum]

Not too long ago I got a 2nd hand Lumicon UHC filter and I have been really impressed with it. Eta Carina in particular shows a huge improvement in size and detail.

So I was wondering whether an OIII filter would be useful in my scope and conditions (10" GSO Dob, dark skies, a little white light pollution to the NE)?

Is the 10" a bit small, are the benefits of OIII only for a few objects cf the UHC? Any other comments?

[Kevnool (Kev)]

I use a 10` with the 03 filter and its magnificent eta is strikingly superb, so is thors helmet in which you need the 03 to observe it, also i think off hand ngc3199 the big banana and plenty more .......It is an essential with any big aperture scope....cheers kev

[monoxide]

an O-III filter is great for when the moon is up too, certainly the best filter for PN viewing.

[Zuts]

Hi,

I have an Astronomic OIII 2 inch filter. I dont use it much as I dont do a lot of visual observing and mainly use the Astronomic UHC. However when I do use it it's great. It's one of those things that if you can get it you will probably keep it as long as you have a scope as it's good quality and sometimes comes in handy. A worthy accesory IMHO.

Paul

[ausastronomer (John Bambury)]

Hi,

I have the Astronomiks UHC and OIII and use both in my 10"/F5 and 18"/F4.5.

To be honest there are only a handfull of targets where you would notice a significant gain by the OIII over the UHC, in a 10" scope. Whilst the OIII works well on many targets the UHC does equally well on about 90% of those same targets. On most targets where the OIII would be the filter of choice, the UHC will achieve 90% to 95% of the gain the OIII achieves. Importantly, the UHC works on a wider range of targets than the OIII. For instance in my 18" scope the UHC helps significantly on the Horsehead Nebula. The OIII is useless on the same target. As mentioned above , the converse rarely applies where the OIII works and the UHC does nothing. Also keep in mind that while the Astronomiks OIII is less aggressive than most OIII filters, in that it blocks out less of the background stars and detail, it is clearly way more aggressive than any UHC and will block a lot of the background stars and detail from combined emission nebula and Clusters in a 10" scope.

If money is no object you could certainly use both from time to time. But, if money is a consideration in any way, I can think of plenty of things to buy before adding an OIII filter to your arsenal, considering you have a 10" scope and already have a very good UHC filter.

Cheers,
John B

[jjjnettie (Jeanette)]

The Veil is another object that looks it's best through an O111 filter.
On the other hand though.
I used to have a UHC filter, but sold it on, now I have the O111, and find I don't use it half as much as the UHC. You're definitely limited to the number of objects you can use it on.

[wavelandscott (Scott)]

Originally Posted by ausastronomer

Hi,

I have the Astronomiks UHC and OIII and use both in my 10"/F5 and 18"/F4.5.

To be honest there are only a handfull of targets where you would notice a significant gain by the OIII over the UHC, in a 10" scope. Whilst the OIII works well on many targets the UHC does equally well on about 90% of those same targets. On most targets where the OIII would be the filter of choice, the UHC will achieve 90% to 95% of the gain the OIII achieves. Importantly, the UHC works on a wider range of targets than the OIII. For instance in my 18" scope the UHC helps significantly on the Horsehead Nebula. The OIII is useless on the same target. As mentioned above , the converse rarely applies where the OIII works and the UHC does nothing. Also keep in mind that while the Astronomiks OIII is less aggressive than most OIII filters, in that it blocks out less of the background stars and detail, it is clearly way more aggressive than any UHC and will block a lot of the background stars and detail from combined emission nebula and Clusters in a 10" scope.

If money is no object you could certainly use both from time to time. But, if money is a consideration in any way, I can think of plenty of things to buy before adding an OIII filter to your arsenal, considering you have a 10" scope and already have a very good UHC filter.

Cheers,
John B

Agree whole heartedly...I have a DGM Optics OIII filter as well as their NPB filter. I like them both but the OIII is used as an afterthought...

I think the comment about making an OIII filter an "optional" purchase down the astro goods list if money is a consideration to be spot on...

[Solanum]

Thanks for the replies, I won't put one top of the list then!

[Quark (Trevor)]

Hi Solanum,
Can not recommend the Astronomic OIII highly enough. I regularly use it in the 16" F4.5 scope in my observatory and in my 12" (highly modified) Lightbridge when observing with Kevnool out in the scrub.

The Keyhole through my 31mm Nagler with the OIII in is amazing, it virtually fills the very wide field of view.

Their are many objects that the OIII seems to work well with, NGC2736 Herschells Ray, NGC3199 The Southern Crescent, IC 3199 The Runing Chicken, NGC 2359 Thors Helmet and IC 2944 to name a few.

I also use an 1 1/4 OIII Astronomic in my 14mm Meade UW & 9mm Nagler to great effect on many PN's and on the less extended nebs.

I also have a 1 1/4 Meade Nebular filter which is a broadband filter and find that I really dont use it much at all since the arrival of the OIII's.

The 1 1/4 filters work well in a filter wheel.

Regards
Quark

Regards
Quark

[ausastronomer (John Bambury)]

Originally Posted by Quark

Hi Solanum,

Their are many objects that the OIII seems to work well with, NGC2736 Herschells Ray, NGC3199 The Southern Crescent, IC 3199 The Runing Chicken, NGC 2359 Thors Helmet and IC 2944 to name a few.

Regards
Quark

Hi Quark,

You seem to have got yourself a bit confused with some of these targets.

NGC 2736 while "sometimes" referred to in texts as Herschel's Ray, is more commonly known amongst amateur astronomers as "The Pencil". It is a detached segment of the Vela Supernova Remnant lying about 4 degrees to the East of the main part of the remnant.

IC 3199 is a 15th magnitude galaxy in Virgo and an OIII filter wont help squat with it.

The Running Chicken Nebula is IC 2948 which is attached to the Lamba Centauri Cluster which is designated IC 2944. The OIII helps on the nebulosity (IC 2948) but noticeably dims the cluster (IC 2944)

It is also worth noting that the Astronomiks UHC filter also works very well on the same targets. It doesn't do quite as well on the Pencil as the OIII but still does very well and shows a noticeable improvement over the unfiltered view. You cannot compare the performance of a top quality UHC filter which is a "narrowband" nebula filter to your Meade "broadband" nebula filter. Also keep in mind that even the Meade "narrowband" nebula filter is not near the class of the Astronomik narrowband filter (UHC).

Cheers,
John B

[Quark (Trevor)]

Originally Posted by ausastronomer

Hi Quark,

You seem to have got yourself a bit confused with some of these targets.

NGC 2736 while "sometimes" referred to in texts as Herschel's Ray, is more commonly known amongst amateur astronomers as "The Pencil". It is a detached segment of the Vela Supernova Remnant lying about 4 degrees to the East of the main part of the remnant.

IC 3199 is a 15th magnitude galaxy in Virgo and an OIII filter wont help squat with it.

The Running Chicken Nebula is IC 2948 which is attached to the Lamba Centauri Cluster which is designated IC 2944. The OIII helps on the nebulosity (IC 2948) but noticeably dims the cluster (IC 2944)

It is also worth noting that the Astronomiks UHC filter also works very well on the same targets. It doesn't do quite as well on the Pencil as the OIII but still does very well and shows a noticeable improvement over the unfiltered view. You cannot compare the performance of a top quality UHC filter which is a "narrowband" nebula filter to your Meade "broadband" nebula filter. Also keep in mind that even the Meade "narrowband" nebula filter is not near the class of the Astronomik narrowband filter (UHC).

Cheers,
John B

Hi John,
No I am not confused one bit.
I prefer to refer to NGC 2736 as Herschel's Ray as it was John Herschel, in 1834 that first discovered and sketched this object. I am not at all interested in what anyone else calls this object.

The cat number I gave when refering to The Southern Crescent was also correct however it is NGC 3199 not IC 3199, I appologise for this error, this object was also discovered by John Herschel in 1834 and looks great through the Astronomic OIII.


I, at no stage intimated that I was comparing a Astronomic UHC filter with a Meade broadband filter but I do disagree with your description of the Astronomic UHC as a "narrowband filter". A look at the transmission curves, supplied by Astronomic on Bintel's website, of their UHC and OIII filters clearly demonstrates the difference between a broadband and narrow band filter.

My experience, as a very active observer over the last 25yrs, is that the number of objects that the OIII is usfull on justifies its inclusion in my observing kit. I am fourtunate to have Astronomic OIII filters for both my 1 1/4" and 2" eyepieces and use them both regularly.

I have only just joined Iceinspace. I was a bit hesitant to do so, as living in the remote outback means a lot of brilliant observing weather and I would much rather be out observing, using my equipment than just taking about it.

I am pleased that you seem to be very satisfied with you UHC, as I am with my OIII.

PS: I really dont use the Meade Broadband filter now at all.

Clear Sky's
Quark

[Zuts]

Hi,

I agree with Quark. As I said in my previous post, I have an Oiii astronomic filter and basically it is a very good filter. It wouldnt get as much use as my UHC but when it does on the right object it is great. This filter is definately a keeper and if you can afford them both then go for it as it will make a worthy quality addition to your astro gear.

Paul

[ausastronomer (John Bambury)]

Originally Posted by Quark

Hi John,

No I am not confused one bit.

Yes you are. Re read this line of your post.

Their are many objects that the OIII seems to work well with, NGC2736 Herschells Ray, NGC3199 The Southern Crescent, IC 3199 The Runing Chicken, NGC 2359 Thors Helmet and IC 2944 to name a few.

Clear Sky's
Quark

Dissected as follows:-

NGC2736 Herschells Ray = correct
NGC3199 The Southern Crescent = correct
IC 3199 The Runing Chicken = wrong (Running Chicken = IC2948)
NGC 2359 Thors Helmet = correct
and IC 2944 to name a few = wrong.

The last line is wrong because you are implying that the OIII filter helps on this target. It doesn't. It helps with the associated nebulosity around this target which is IC 2948 (the running chicken), which you have already referred to previously. IC 2944 is an open cluster (Lambda Centauri Cluster). No filter will help showing the stars within a cluster. The filter only helps with the nebula associated with the cluster which has a different IC designation and you've already talked about that target.

But is you want to go on thinking you were right that's fine. Carry on.

A look at the transmission curves, supplied by Astronomic on Bintel's website, of their UHC and OIII filters clearly demonstrates the difference between a broadband and narrow band filter.

You are wrong here also. Neither of these filters is a broadband filter, yet you imply that looking at the curves of both shows the difference between a broadband and a narrowband filter. The UHC is a narrowband filter and the OIII is in fact what's called a "line filter". So how does examining the transmission curves of a line filter and a narrowband filter tell you anything about what a broadband filter is doing, to assist in the comparison ?

I have both an Astronomiks OIII and UHC filter. I know exactly what both of them do. In fact I use the OIII more than the UHC, but I am also jamming them down the throat of either an 18" Obsession or a 25" Obsession, which is significantly different to what the original poster intends to use them in. I also have a 10"/F5 telescope the same as the original poster and know exactly what both the Astronomiks UHC and OIII will do in that scope also.

On the basis that the original poster owns a 10" scope I will re-iterate what I said at the conclusin of my previous post.

If money is no object you could certainly use both from time to time. But, if money is a consideration in any way, I can think of plenty of things to buy before adding an OIII filter to your arsenal, considering you have a 10" scope and already have a very good UHC filter

Note that at no stage did I say it wasn't a very good filter. I said I didn't figure it an "essential" puchase considering he already owned the Astronomiks UHC and was limited by a 10" telescope.

Cheers,
John B