Quote:
Originally Posted by hickny
My scope is however f4.5 which is relatively fast. Your 8" Dob could be f6 or f8 somewhat slower. This may b the reason for the lack of improvement in viewing. Can you verify the quality of the filter? Were you viewing from a dark sky?
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Hi,
Most filters are designed to work well from about F4 to F15 so an F6 to F8 scope really is the "sweet spot" for just about all filters.
Quote:
Originally Posted by AstroGuy
Was it a narrow band or a broad band filter? broadband will let you see more, where as narrow band less and is really only suited for astrophotography longer exposure image acquisition.
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It is neither of these. He already said it was an OIII filter which is in fact known as a "line filter".
I am "guessing" his problem was he was observing under light polluted skies where the filter wont help a lot.
Cheers,
John B