Using 2" filters with the Skywatcher 9x50 Finderscope, what adapters are needed?

[Jannis]

As i'm planing on ordering some 2" NB filters, i'd also like to be able to give them a try on the finderscope with the help of the QHY5L-II-M.

I see the front of the finderscope have threads, but i have no idea what size, and no idea what adapters i would need to make a 2" filter fit. Can someone help me out with this? I have the black verson of the finderscope that came with the Explorer 200PDS.

I know one usually would put the filter behind the scope, but the only way a 2" filter would fit on the finder would be in the front.

[Thalestris24]

Hi

Measuring the internal diameter of my sw finder suggests it's either m50 or m51 and 2" filters are m48. I'm afraid I don't know of any suitable adapters. I suppose you could fix a filter in place using some ptfe tape but it would be a bit risky. You can get lens adapters to m48 which allow you to attach a 2" filter to the front of a camera lens.

Louise

[Jannis]

Thanks. I've been looking into step-down rings to 48mm, but i need to know what size to step down from. Can anyone confirm the thread size of the finderscope?