Haloes around bright stars

[Lee]

I was imaging a bright star last night, using Astronomik LRGB filters, and have noted that the G & B images have fairly strong haloes... L & R are unaffected.. This was through the f/4 newt, Baader MPCC before the filters, Atik 428EX CCD.
Does anyone else see this? Is there a fault/problem??

First image is the R frame, then G then B

[pmrid]

Lee, the answer is yes, I have - I assume you mean their Series 2c filters.

I have had a lengthy exchange with Astronomik about exactly this problem. And in the end, they approved a return and refund which has now been processed by OPT without any argument.

I have also recently noted that strong halos were also forming around a Baader OIII filtered image of bright stars - but not Ha or SII. The thing they had in common was the camera. I haven't spoken with Baader about their filter but Astronomik have suggested strongly that the problem is one of reflections and that the cause lies as much with their filter as with the coating on the front window of the camera. Same manufacturer as yours by the way but different camera.

Peter

[Shiraz]

Hi Lee. I have a similar setup with Astronomik filters - no halos at all with RGB. Had one slight halo around a very bright star with an Astronomik Ha filter, but nothing more than a very minor cosmetic problem - had to look hard to pick it.

Maybe there are batch problems with the filters if you and Peter have had issues?

[Lee]

Yes, series 2c, new this year...
Was your problem only with green and blue also??



I've got an old Ha filter, that exhibits halos, I was going to replace it sooner or later.... I don't find the halo that bad to be honest, I don't do much RGB in any case! I do like having all the same make filters for their par-focality....

Lee

[pmrid]

Another point worth mentioning is that my setup that produced thes halos is working at between F3.9 and 5.3 - the halos with the G and B were at 3.9 (i.e. I was using a Takahashi .73 reducer. I had heard that the faster the scope the more prone to reflection issues.

Peter