Hi all, I would like to share a very strange experience: I processed (pixinsight) two sessions of capture (newton 150F4) on M104 with flats (Lacerta flatbox withFlat wizard from NINA) per session and got a very strange linear ondulated background as seen in the attachment. To make it short I found that this background was coming from the flats as can be seen in one individual flat (debayered). Surprinsingly it is not showing the same way on the masterflat that looks normal but most probably keeps tracks on this at a decimal level. The side by side crop show clearly the same "frequency" in the master light as in the flat. I found too that if I do flats on the blue sky (not with my lacerta flatbox) I do not have this linear ondulation on the background. What is strange is that I used this lacerta flatbox a lot of times before without noticing this problem in any masterlight. When I zoomed on the masterlight this time it was obvious that something got wrong. It looks as an interference pattern maybe generated by the combination of the flatbox, the L-pro filter in front of the baader MPCC and the baader matrix on the camera. As you can see, the pattern is aligned with the largest dimension of the sensor and doesn't rotate if I rotate the flatbox.
Has anybody ever had the same experience? any idea? To solve my problem I switched on doing flats on the blue sky just after sunset but I most probably have some light leak problem now.
CS Frédéric
Has anybody ever had the same experience? any idea? To solve my problem I switched on doing flats on the blue sky just after sunset but I most probably have some light leak problem now.
CS Frédéric
