[Stefannebula (Stefan)]

Hello all

I am imaging at F2.8 (SharpStar HNT 150 F.28) and I have just been using entry-level 7nm Optolong Ha, Sii and Oiii filters. I see some pretty nasty halos with these filters so I have been considering upgrading.

I have also been reading about the center wavelength shift that occurs at faster focal ratios, so I have been considering getting some 'fast' filters that are specifically tuned to account for this shift.

I know Baader has some high-speed filters but from what I've read they likely have a larger bandpass ~12nm. I am looking for something more in the range of 3-5nm. I know Chroma makes some, and Astronomik has a new series of fast narrowband filters but I haven't heard much about how either performs.

Does anyone here have experience with any of these 'fast' filters? Or could I get away with imaging at F2.8 with regular 5nm filters?

Thanks,
Stefan