Tue, 06/18/2024 - 23:07
I have a lead on a set of Astrodon V, B, and Ic filters. I understand in 2012, the B filter was revised to address a red leak. Does anyone know if there's an easy way to tell by looking at the filter or packaging if an Astrodon B is pre- or post- red leak fix? Thanks!
The edge of the filter is blackened. There was a stick-on label that indicated the filter bandpass and the lot number. The B filter went through 3 iterations. B had little blockage (and I think did not have a blackened edge). B** was better, but still not great. B*** was the final filter and was properly blocked.
Arne
Excellent, thank you! Is an older B* or B** filter worth using? If not, is it better to use an Astrodon V* and Ic* with a different brand (Chroma / Baader / Optolong) for B, or would I be better off sticking with one source for all three?
In general I'd say it is better not to mix filters from different makers. The exception would be for systems in which it is easy to apply (i.e. automatically) a focus offset correction. You don't need a perfect match of focal points but you won't know how far off the focus gets until you actually put the filters in your system.
For example, my system has Astrodon B, V, I fiters and a Custom Scientific Rc filter. If I don't apply an offset the Rc star images are donuts. This would be too much for me to accept without a correction.
Phil