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Originally Posted by Logieberra
Thanks for the info guys.
Thanks Peter, I'll give the Astronomik a go and keep Borg in mind. Is your IDAS a 2" thread in variety? Are you using that with your narrow filed barlow setup as well? I've seen your results with the 2x barlow on that galaxy. Impressive. Borg do make good stuff (I'm also considering their version of the OAG, though Phil suggests I go with the tried and tested MMOAG - as he has done).
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Hi Logan,
Yes, I'm using the 2" screw on IDAS LP Filter. There is an excellent write up on this filter in Ron Wodaski's Book "The New CCD Astronomy" see pages 300,301. Ron remarks that the IDAS has excellent colour balance compared to several different filters (though not the ones you are considering). He also says: "It slightly darkens red, but blue and green are left in very good shape."
That M83 image of mine is a hogpog of different configurations of the barlow and ONAG with and without the IDAS. Even the image scale has varied. Exposures need to be longer with the IDAS but I feel I'm miles ahead in terms of gradients and SNRs.
Peter