Two items on my to-do list are planetary imaging and photometry. As I was looking into planetary imaging filters I saw references to some people using their z’ (for instance) as an IR pass filter. Venus is often images with a UV pass filter. I thought, wouldn’t it be nice if I could just use the photometry filters instead of buying two sets! That got me looking into Johnso-Cousins vs Sloan. From my brief reading it sounds like there is a shift toward Sloan and that Sloan has sharper cutoffs. The general question is which filter system should I get. Specifically, Question 1) Does anyone have experience using photometic filters for planetary astrophotography that would lead you to prefer one system over the other? My intuition is that sharper cutoffs is a good thing. Question 2) Does the photometry community prefer one system over the other?