I mentioned yesterday BORG systems well consider using filters. This is another example. Kenko R60 is very convenient and economical tool to play around. Since it is the absorption type of filter, there is no spectrum shift off-axis and little reflection issue. So quite easy to use. Here is one example.

R60 is set in front of 71FL and LPS-V4 in front of super reducer. For regular RGB image, just take R60 out from the optics and set is back for Ha imaging. As mentioned several  times here, LPS-V4 creates very good color balance for one-shot color cameras. Ha’s bandpass is not as narrow as other Ha filters. But this achieves 19nm width (I think not bad) and by removing and re-setting R60, you can creates Ha image and regular RGB without re-focusing. It allows to focus without R60. So stars don’t get too dim for focusing.  Since there is no spectrum shift issue, you may set it in front of wide-angle lenses which don’t allow to work with the interference coating such as LPS filters.


~ by tedishikawa on November 22, 2011.

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