QHY9 - 1.25' filters and Vignetting

[dp297 (Dimitris)]

I have a QHY9 coupled to a Starlight Xpress wheel or to a TS drawer. I really want to switch from my 2'' Baader filters because I want to save money and get Astrodon narrowband.
Does anyone have any experience on the amount of vignetting I am expected to have? Can I get away with it or do I have to go to 36mm?

Thanks

[billdan (Bill)]

Hi,

I asked the same question in the Eyepiece and filters forum but did not receive a reply.

Since then I found the answer on SBIGS website, and unfortunately for my QHY12 APS/c chip I have to use 2 inch filters.

The smaller KAF8300 chip is OK with a 36mm filter. You won't be able to use the 1¼ inch filters though, according to SBIG.

Regards
Bill

[Chris85 (Chris)]

I'd say unfortunately you'd need to use something bigger. With my 383 I had to upgrade to 36mm filters to deal with vignetting when using 1.25".