Rapidly passing cloud meant I tried something radical for me today with my Ha full disk: I used a focal reducer. This only needed 2 panes to make the full disk, however using focal reducers with PST mods means sweet spotting is accentuated, and this in indeed the case with this disk where on the west (right) hand side the image can be seen going off band. When we finally get some decent clear skies I may explore this setup a bit more...