possible faulty Oiii filter

[lensman57]

Hi,

Is there a way to determine if an Oiii filter is faulty or not? I have two Baader 1.25" Oiii filters, one is the plain old visual version the other is the CCD version. I have yet to get an image with the Oiii filter without huge halos around the stars in fact it is just as bad as the  visual version for producing halos. I have tried it with 3 different scopes with the same result, an SW ED 80, WO ZS 71 and an Ascension triplet, all producing halos. Thanks for any tips or help.

Regards,

A.G

[ronin]

An OIII filter is specified by wavelengths it blocks or passes so should be the same whether visual or imaging. So I would expect what occurs on the visual to be the same as on the ccd version. To be honest if there was a differnce then I would suspect that one is not as specified, but if they both produce the same (problem) then you seem to have 2 OIII filters doing the same.

Do you get halos when you look through either as in visual only.

[D4N]

I would imagine that a visual Oiii filter would not require the same level of UV/IR cut as an imaging one. Not a great deal of point in blocking stuff you can't see.

Sent from my iPhone using Tapatalk

[NGC 1502]

Hi A.G.

By process of elimination, it's not the scope that's the prob, you've tried 3 different ones ( unless all 3 had dewed up objectives that produced halos )

Could it be the CCD ?  Or image processing ?

Is the CCD version new ?  You maybe could contact the supplier, depending on who they are, may have a spot on answer, or not.  How about exchanging it ?  Or maybe there's someone you know who has another filter to try ?

Hope you sort it, Ed.

[lensman57]

Hi A.G.

By process of elimination, it's not the scope that's the prob, you've tried 3 different ones ( unless all 3 had dewed up objectives that produced halos )

Could it be the CCD ?  Or image processing ?

Is the CCD version new ?  You maybe could contact the supplier, depending on who they are, may have a spot on answer, or not.  How about exchanging it ?  Or maybe there's someone you know who has another filter to try ?

Hope you sort it, Ed.

Thank you ED,

The CCD is less than 6 months old, the only other option is to try and use it with a 150PDS and see what happenes. Will keep you informed.

Regards,

A.G

[swag72]

Do you know anyone close enough that has a different make of camera for example? This would help you to rule out the glass sensor cover.

[lensman57]

Do you know anyone close enough that has a different make of camera for example? This would help you to rule out the glass sensor cover.

Hi Sara,

I had thought of the glass I even thought it may have had something to do with the FF/FR. With regret I don't know anyone around or nearby. I have an Atik 16IC perhaps I could it a go and see if I still get the same halos.

Many thanks and regards,

A.G

[swag72]

The only reason I am suggesting this is that there was a thread that I started back last year about odd gradients with the OIII filter. After that, a few people also noted that they had the same thing. The common factor was that the camera's were all Atiks. People were using different scopes and filter wheels. I tried all sorts to eliminate the gradient and at some stage Atik was quite interested in getting to the bottom of it.

Sadly that enthusiasm was short lived and I've now changed to a different make of camera. The upshot is that I have no OIII gradient.

[ChrisLX200]

I do notice star halos with the Baader OIII filter which are not present on their Ha filter. I don't believe anything else is responsible other than the filter itself, but it is a matter of degree - post some images for comparison. This is another reason I'm considering moving to an Astrodon narrowband set.

ChrisH

[ollypenrice]

The bandpass of the visual one is far wider and should produce far less contrast.

I find that the 0111 Baader CCD is halo prone in the FSQs to a far great extent than it was in the ODK14. While the filters may be faulty I have to say that I've had this trouble with Astronik Ha filters both before and after replacement. The later Astronomik Ha was better than the first but not as good as the Baader.

I think luck plays a part in all of this. It can just happen that your light path can have the lucky or the unlucky separations between glass surfaces. This is only a guess, mind. It would be worth asking Baader.

It isn't too big a problem for me because I don't do pure NB images and tend to replace my stars in HaO111RB images with RGB-only stars anyway. It would be nice not to have the problem, though!

Olly

[lensman57]

The only reason I am suggesting this is that there was a thread that I started back last year about odd gradients with the OIII filter. After that, a few people also noted that they had the same thing. The common factor was that the camera's were all Atiks. People were using different scopes and filter wheels. I tried all sorts to eliminate the gradient and at some stage Atik was quite interested in getting to the bottom of it.

Sadly that enthusiasm was short lived and I've now changed to a different make of camera. The upshot is that I have no OIII gradient.

All this sounds very familiar to me, the last time I managed to do anything with the Oiii was last year on the Rosette, I had to do a star removal on the Oiii and then combine the Ha with the stars otherwise it would have been unusable. I also did follow your  thread last year but I thought that it got sorted out ot your satisfaction. I also send Atik an email regarding some gradients that I always get at the borders of the image when using the 428EXC ( the borders are always green ) but they didn't come back to me. I guess there is always Starlight Xpress or QSI .

Regards,

A.G

[RikM]

The bandpass of the visual one is far wider and should produce far less contrast.

The Baader visual filter is 10nm and the CCD version is 8.5nm, according to the info on the FLO web site. Would that be a very noticeable difference? I am just about to start playing with a Baader CCD filter next clear night but don't have the visual version to compare to.

[ollypenrice]

The Baader visual filter is 10nm and the CCD version is 8.5nm, according to the info on the FLO web site. Would that be a very noticeable difference? I am just about to start playing with a Baader CCD filter next clear night but don't have the visual version to compare to.

I hadn't looked up the bandpasses and the difference is less than what I would have supposed. I do have both the visual and the CCD Baaders but since changing them is a palaver I'm going to apologize and bow out!

Olly

[RikM]

I was surprised they were that close as well. They do say that the Baader visual filter has a narrower bandpass than most other visual filters.