I tried my latest configuration of my CaK filter today, rearranging the order and spacing of the optical elements with a view of minimising any ghosting and reflections; while this is not banished it is a lot better than it was previously, maybe something I can live with now. In this shot taken with the 40mm scope at f20 with the DMK31 camera, there were huge proms visible today, and these could also just be seen in CaK wavelengths. A good result today!