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Equipment Discussions >> Eyepieces

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Greg77
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Reged: 05/02/09

Loc: Slovenia, EU
Re: OIII Filter Choice new [Re: John Huntley]
      #5433780 - 09/22/12 01:53 AM

Quote:

Prior to the Astronomik I'd tried the Telescope Services 0-III (which is the same as the Skywatcher one) and the Baader...




John,

...how would you describe diference between TS and Astronomik in terms of contrast and brightness of background stars (field)?

CS!

Greg


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Giorgos
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Reged: 01/14/11

Loc: Athens, Greece
Re: OIII Filter Choice new [Re: Greg77]
      #5433825 - 09/22/12 03:01 AM

I have tried side by side the Lumicon and the Meade O-III (908X). The nebulae trough both of them seem more or less the same the Lumicon gave a pinkish tint to stars though. I prefer the Meade that shows more natural color on stars.

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Richard Low
professor emeritus
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Reged: 11/27/05

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Re: OIII Filter Choice new [Re: Giorgos]
      #5433827 - 09/22/12 03:11 AM

I have the Celestron O-III which works well with great contrast on the Veil Neb. in my 15" dob. I recommend to get filters in 2" versions as it is very useful on 2" widefield eyepieces 30-40mm.

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reiner
sage
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Reged: 09/28/05

Loc: Freiburg, Germany
Re: OIII Filter Choice new [Re: David Knisely]
      #5433848 - 09/22/12 03:57 AM

Quote:

The Astronomik has a full width at Half Maximum (FWHM) of a whopping 204 angstroms (the Lumicon OIII is around 115 angstroms for example).




Hi David,

this is true for the older Astronomic OIII filters. According to their website, they have reduced the bandwidth now to 12nm, which is perfect for an OIII filter. It is on the german webpage only
http://www.astronomik.com/de/visual-filters/oiii-filter-visuell.html

I haven't tried one of these newer ones, though.

@all: I have compared extensively the Baader and the Lumicon. Sure, the Baader offers excellent contrast on the Veil and other bright OIII sources. If it comes to faint targets, like some faint Abell PNe, the Lumicon is a considerably better choice.


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Scanning4Comets
Markus
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Reged: 12/26/04

Loc: Ontario, Canada
Re: OIII Filter Choice new [Re: reiner]
      #5433858 - 09/22/12 04:19 AM

I don't see why some people have to be so "nit picky" about a few Nm here. Sure the Lumicon has a wider bandpass, but there really is NO POINT in spending $200.00 or more on a 2" filter when you can pretty much get the same results with the Baader / Celestron. This is supposed to be a "fun hobby", not a competitive one.

If you feel the need to go out and blow that kinda cash all the power to ya bro, knock yourself out,


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sixela
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Reged: 12/23/04

Loc: Boechout, Belgium
Re: OIII Filter Choice new [Re: Scanning4Comets]
      #5433862 - 09/22/12 04:27 AM

Well, "a couple of nm" makes a lot of difference. One of the two OIII emission lines is only partially transmitted on the Baader on some samples.

As Reiner said, it can help on some things and hinder on others.


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David Knisely
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Reged: 04/19/04

Loc: southeastern Nebraska
Re: OIII Filter Choice new [Re: reiner]
      #5433869 - 09/22/12 04:47 AM

Quote:

Quote:

The Astronomik has a full width at Half Maximum (FWHM) of a whopping 204 angstroms (the Lumicon OIII is around 115 angstroms for example).




Hi David,

this is true for the older Astronomic OIII filters. According to their website, they have reduced the bandwidth now to 12nm, which is perfect for an OIII filter. It is on the german webpage only
http://www.astronomik.com/en/visual-filters/oiii-filter-visuell.html

I haven't tried one of these newer ones, though.

@all: I have compared extensively the Baader and the Lumicon. Sure, the Baader offers excellent contrast on the Veil and other bright OIII sources. If it comes to faint targets, like some faint Abell PNe, the Lumicon is a considerably better choice.




It would be nice if an independent spectrophotometer transmission curve would be provided by Astronomik (even Orion does that). The PDF sheet shows a "generic" curve which can be roughly estimated to have a FWHM of about 123 angstroms which, if accurate, could work pretty well (about as well as the Lumicon OIII).

However, I have to take strong issue with what Astronomik says about the OIII filter:

"Since enough light must be available to make use of the OIII filter it is best to use this filter with apertures of more than 6" (150mm). Smaller instruments do not gather enough light for meaningful and satisfying astronomical work."

This is an often-quoted myth and is definitely *not* true. As I have stated in the past, I have used the OIII in apertures of 50mm and larger with good results. Indeed, one of my favorite views of the North America Nebula comes in my 100mm aperture f/6 refractor at 15x and 25x using the OIII filter, so it definitely does work in smaller scopes. The larger the aperture, the more objects (and detail) will be visible that the OIII will help with, but this does not mean that its use is limited to apertures larger than six inches. It would be nice if Astronomik would not continue to perpetuate this myth. Clear skies to you.


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Jon Isaacs
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: OIII Filter Choice new [Re: Starman1]
      #5433885 - 09/22/12 05:47 AM

Quote:


The point to be made here is that a slightly narrower bandwidth would enhance the contrast more, but at the expense of the stars. So which do you use the nebula filter for--nebulae, or views of stars? I'm not being sarcastic because there really is a difference in preference involved.




Don:

A good point... Myself, when I want to enhance the view and but still see a good number of stars, I use an Orion Ultrablock. When I want to maximize the contrast, I use a narrow band filter.

Jon


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Traveler
Pooh-Bah


Reged: 08/19/07

Loc: The Netherlands
Re: OIII Filter Choice new [Re: David Knisely]
      #5434023 - 09/22/12 08:42 AM

That is true David about the OIII and aperture myth. I use my Astronomik OIII filter even with my Tak FS60C and enjoyed the views very much. That is what i learned from you by the way.

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David Knisely
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Reged: 04/19/04

Loc: southeastern Nebraska
Re: OIII Filter Choice new [Re: Scanning4Comets]
      #5434516 - 09/22/12 02:01 PM

Quote:

I don't see why some people have to be so "nit picky" about a few Nm here. Sure the Lumicon has a wider bandpass, but there really is NO POINT in spending $200.00 or more on a 2" filter when you can pretty much get the same results with the Baader / Celestron. This is supposed to be a "fun hobby", not a competitive one.

If you feel the need to go out and blow that kinda cash all the power to ya bro, knock yourself out,




Well, it isn't really "competition". There have been a number of reports of somewhat variable quality in the lower priced OIII filters like those from Zhumell and Celestron. With these extremely narrow bandwidth filters, any notable variation in the transmission characteristics can result in vastly different performance. The Baader in particular is quite narrow, so it cuts a little into the 4959 angstrom OIII line, while the slightly broader filters transmit it. I suspect that the Celestron filters (if they are actually re-branded Baaders) may be produced in-bulk in ways that cause less than high quality filters to get through. For the most part, the higher priced filters tend to be made with somewhat more consistent passband locations and widths, which is one reason I have always bought from Lumicon. This does not mean that you will always get a perfect filter from them, but in my experience, the quality of the Lumicon filters has been fairly high. With the Celestrons, well, it looks like kind of a roll of the dice. Clear skies to you.


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turtle86
Pooh-Bah Everywhere Else
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Reged: 10/09/06

Re: OIII Filter Choice new [Re: Starman1]
      #5434542 - 09/22/12 02:21 PM

Quote:

Quote:

Quote:

Another vote for the Astronomik. I've compared it against others, and it is the best in my refractor. A friend has a C9.5. We checked the Astronomik against the Baader in both scopes. We agreed the astronomik was the clear winner.

But of course beware that the performance of such restrictive filters are very affected by aperture and quality of the sky. Regards.




Yet another vote for the Astronomick. I have the narrow band, OIII and H-beta filters all on a filter slide. All work great for me. The OIII might be a little broader than the Lumicon, etc., but the Veil really pops out when I use it in my scope, showing exquisite filamentary detail. Another standout is Thor's Helmet. Just a great filter for planetary nebulae (and the Veil).

Two things I really like about the Astronomick. One, they have very durable coatings, which are essentially scratch-proof and impervious to dew. Two, the view is very aesthetically pleasing, with nice pinpoint stars. In contrast, a couple of the other OIII filters I've seen (the older version of the Lumicon specifically comes to mind) yielded rather funky-looking bloated stars...




The point to be made here is that a slightly narrower bandwidth would enhance the contrast more, but at the expense of the stars. So which do you use the nebula filter for--nebulae, or views of stars? I'm not being sarcastic because there really is a difference in preference involved.
The TeleVue O-III is a broader one and also of superlative quality. It really does depend on preference.




No sarcasm taken, but I was actually talking about the quality of the stars being seen, not the quantity. I used to have one of the older Lumicon OIII filters, but the stars were bloated or halated. In comparing it to the Astronomik, I found that the latter yielded much nicer stars and enhanced the contrast at least as much. I agree with Jon that it's helpful to have different filters depending on how much contrast you want. With my filter slide I like to switch back and forth between the OIII and narrowband when viewing a nebula--for some objects one filter will clearly work much better than the other (Veil and OIII, Horsehead and H-beta, etc.), but for a lot of objects both the OIII and narrowband filters work pretty well, with each filter emphasizing different nebular details.


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turtle86
Pooh-Bah Everywhere Else
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Reged: 10/09/06

Re: OIII Filter Choice new [Re: reiner]
      #5434546 - 09/22/12 02:23 PM

Quote:

Quote:

The Astronomik has a full width at Half Maximum (FWHM) of a whopping 204 angstroms (the Lumicon OIII is around 115 angstroms for example).




Hi David,

this is true for the older Astronomic OIII filters. According to their website, they have reduced the bandwidth now to 12nm, which is perfect for an OIII filter. It is on the german webpage only
http://www.astronomik.com/de/visual-filters/oiii-filter-visuell.html

I haven't tried one of these newer ones, though.

@all: I have compared extensively the Baader and the Lumicon. Sure, the Baader offers excellent contrast on the Veil and other bright OIII sources. If it comes to faint targets, like some faint Abell PNe, the Lumicon is a considerably better choice.




Interesting. I wonder when Astronomik made that change.


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Scanning4Comets
Markus
*****

Reged: 12/26/04

Loc: Ontario, Canada
Re: OIII Filter Choice new [Re: turtle86]
      #5434579 - 09/22/12 02:41 PM

Don:

Quote:

A good point... Myself, when I want to enhance the view and but still see a good number of stars, I use an Orion Ultrablock. When I want to maximize the contrast, I use a narrow band filter.

Jon




This is only good if the object in question emits the right emission lines and you need the right filter for maximum contrast. Makes no sense having to use an Ultrablock on an object that would need an O-III filter for the best contrast and having the need to see more "stars". The whole point is to maximize contrast on the nebula and not stars.

Quote:

No sarcasm taken, but I was actually talking about the quality of the stars being seen, not the quantity. I used to have one of the older Lumicon OIII filters, but the stars were bloated or halated. In comparing it to the Astronomik, I found that the latter yielded much nicer stars and enhanced the contrast at least as much.




As far as "stars" go filter wise, these filters are meant to enhance the view of nebulae, not stars. The only reason you would need to see any stars in an O-III or UHC / Ultrablock filter is for focusing. True what you said David about more expensive filters having better QC, I guess I was lucky with my Celestron O-III as it does work really well.

O-III filters work best when fully dark adapted with the right exit pupil. I find mine is only too dark when I am not adapted to the darkness and excellent when I am fully dark adapted. I have also tried it at higher powers, with less than satisfactory results. This is when I pull out the Orion Ultrablock because it has a wider bandpass. If the nebula requires an O-III filter at higher powers, I'll try to gain maximum contrast by not bumping the power up too much.

So for me, I now use my Celestron O-III filter with my 38mm Orion Q-70, 17mm Baader Hyperion, (which will be replaced with an 18mm Meade HD 60), 10.5mm pentax XL, and once in a while on my 7mm XW, but rarely on the 7mm XW at all. At higher powers I'll switch to the Ultrablock and sometimes I will use the Ultrablock at lower powers because the nebulae in question will emit certain lines in which the Ultrablock shows better contrast.

Good examples are M-8, M-27, M-20, etc.

38mm Q70: 7.9mm exit pupil
17mm Hyperion: 3.7mm exit pupil
10.5mm XL: 2.4mm exit pupil
7mm XW: 1.6mm exit pupil

Cheers,


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turtle86
Pooh-Bah Everywhere Else
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Reged: 10/09/06

Re: OIII Filter Choice new [Re: Scanning4Comets]
      #5434627 - 09/22/12 03:13 PM

Quote:

As far as "stars" go filter wise, these filters are meant to enhance the view of nebulae, not stars.




No disagreement there, but if two filters enhance the view of nebulae equally well but one of them also has tighter stars, why not get the filter that does both well?


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Scanning4Comets
Markus
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Reged: 12/26/04

Loc: Ontario, Canada
Re: OIII Filter Choice new [Re: turtle86]
      #5434635 - 09/22/12 03:16 PM

I re-edited my post. If you have read an earlier post I made, two friends and myself tested my Celestron O-III along with a Lumicon O-III. The Lumicon showed a wider bandpass and a few more stars, with "stars" not being of importance. The difference wasn't huge or big by any margin, but it was there to a "slight" degree. The test was done on M-17, The Swan, or "Omega" Nebula.

I just don't see the point in running out to spend over $200.00 + to get a 2" Lumicon for 4 Nm more of bandpass when I am happy with the Celestron O-III. Others may want to do that, which is ok. Mine is probably worth $80.00 or just less than that. This is my point. I can more than get by with what I have now and the results are more than satisfactory. I used to own Lumicon filters exclusively and I *can* see a very "slight" difference, but to me the difference isn't that much at all.

Cheers,


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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

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Re: OIII Filter Choice new [Re: Scanning4Comets]
      #5434705 - 09/22/12 04:10 PM

The biggest difference is throughput. The Baader filter is a very "dark" O-III filter due to its tighter bandpass and less efficient throughput on those bands that it does pass. As another poster said, it works better with brighter O-III sources in smaller scopes or larger scopes, but honestly in a small aperture scope you're not going to be looking at many dim O-III sources anyway.

In a big scope, the lower transmission of the Baader is less relevant save for threshold targets, and for those, there's always a bigger scope. To me, the job of a filter is contrast, not natural stars or a lot of stars. I'd rather have my starry vistas entirely unadulterated by a filter. But for those who like a mix of stars with their O-III sources, I'd look at a gentle filter like the Televue O-III. Lower contrast on O-III sources, but a nice mix of broader spectrum sources and enhanced O-III sources.

Regards,

Jim


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Jon Isaacs
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: OIII Filter Choice new [Re: Scanning4Comets]
      #5434816 - 09/22/12 05:46 PM

Quote:

A good point... Myself, when I want to enhance the view and but still see a good number of stars, I use an Orion Ultrablock. When I want to maximize the contrast, I use a narrow band filter.

Jon

Quote:






This is only good if the object in question emits the right emission lines and you need the right filter for maximum contrast. Makes no sense having to use an Ultrablock on an object that would need an O-III filter for the best contrast and having the need to see more "stars". The whole point is to maximize contrast on the nebula and not stars.





Wait, wait...

You seem to be solely focused on maximizing the contrast of the nebula you are observing. Don added an interesting perspective, it's up to the observer, one does not have to be solely focused on getting the best possible view of the nebula, sometimes seeing the starfield and the nebula is of interest.

As I pointed out, if that is my interest at the moment, then I will use the Ultrablock, it provides a nice balance because it enhances the contrast of many nebulae while still showing a reasonable starfield. M8, M17, the Rosette, these are few that have interesting starfields and are bright enough the Ultrablock makes for a pleasing view.

Of course, there are times too when I am interested in maximizing the contrast of an object, then I will use either an O-III filter or an H-Beta... This is most often the case, the Ultrablock gets relatively little use in comparison.

So as Don pointed out, it's a choice we all have. And too, we all have the choice of viewing without any filtering. That is good too.

As far as the Celestron O-III goes. I reported here a comparison a friend and I did between my Celestron O-III, his Celestron O-III and the TV Bandmate O-III. We used a 17.5 inch Dob. The object was the Veil and my Celestron O-III showed the most contrast, the TV definitely enhanced the contrast, the other Celestron O-III was barely better than nothing.

But since then, I have not seen other reports of poor performing Celestron O-III filters and I have seen many reports that they are good performers so I have to think my friend's was an anomaly rather than typical.

Jon


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MadHungarian
sage


Reged: 11/18/10

Loc: Rainy WA
Re: OIII Filter Choice new [Re: reiner]
      #5435347 - 09/23/12 12:56 AM

Quote:


...
this is true for the older Astronomic OIII filters. According to their website, they have reduced the bandwidth now to 12nm, which is perfect for an OIII filter. It is on the german webpage only
http://www.astronomik.com/de/visual-filters/oiii-filter-visuell.html
...





I'm the market for a middling-narrow OIII myself, so then it looks like the new Astronomik might be the one for me (I'd do Lumicon, but they seem to have dropped off the face of the earth). Astronomik hadn't been my front-runners before because they had a reputation as being wider, and i already have a (wider) UHC.

But the $199 question is, how do i know i'm getting one of the new Astronomiks? If i buy from Opt/etc today, i'm most likely getting a unit they've had in stock for awhile, so it'll probably be an old one.

Though I have another concern -- I ran the webpage above through Google Translate and i see no mention of recent changes to the filter, so is there any way of finding out if the filter bandwith actually has changed or whether the 12nm figure it mentions is just a webpage mistake?


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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: OIII Filter Choice new [Re: Jon Isaacs]
      #5435348 - 09/23/12 12:56 AM

Since 2005, the bandwidth of the Lumicon O-III has excluded red colors, so there is no visible red in the newer Lumicon filters.
They changed the filters BECAUSE people complained about the lack of tightness of the star images. It turned out that red and blue-green weren't focused at exactly the same point and this bloated the stars.
My current version (well, 2010), has only blue-green transmission. When you look through it in the daytime, that's all you see. I have an older 1.25" one which appears reddish when you look through it in the daytime. In that one, there was a broad swath of red that was transmitted.


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David Knisely
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Reged: 04/19/04

Loc: southeastern Nebraska
Re: OIII Filter Choice new [Re: turtle86]
      #5435351 - 09/23/12 01:01 AM

turtle86 wrote:

Quote:

No sarcasm taken, but I was actually talking about the quality of the stars being seen, not the quantity. I used to have one of the older Lumicon OIII filters, but the stars were bloated or halated.




Those were the very old laminated filters. Lumicon no longer uses that method of protection. In addition, Lumicon's OIII no longer has the "red leak" secondary passband, so the images of stars tend to be not terribly "bloated" or having red secondary star images anymore (at least mine doesn't). Clear skies to you.


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