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Showing results for tags 'reflection'.
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I've had continual problems with reflections in my flats. I have an Atik 383L, an Atik EFW2, and I use 36mm unmounted Baader filters. It seems that when using the camera and wheel 'as intended' I get reflections. I see these especially in my flats, but I think they are there in the images too. They do not calibrate out - I am left with lines in my images and I either have to crop them heavily or use blunderbuss processing techniques, which inevitably leads to some degradation in image quality (and my images are already quite degraded enough). I have posted about this problem before: https://stargazerslounge.com/topic/260450-horizontal-lines-in-flats/ and https://stargazerslounge.com/topic/269119-does-atik-efw2-work-with-atik-383l/ There is a solution, but it is not ideal. I thought that I would provide an update as to my progress and post my solution. If anyone has any other ideas I would consider trying them out. I am struggling to believe that I am the only person having this problem. First off, here is the issue - it appears to me to be a reflection of either the optical window edges or the sensor itself (I've pushed the contrast a bit to make the issue obvious in a reduced size JPEG): The issue is most obvious in the NB filters, but it is there in the RGB too - perhaps worse in the blue filter. I have tried the set up on 4 separate scopes - 3 x refractors and 1 x SCT - there is no difference I have tried two different 383L cameras - they both cause this problem I have tried 2 different sets of Baader LRGB filters (thanks to FLO for supplying the second set) and a set of Baader NBs - no difference I have tried reversing the orientation of the filters in the carousel (suggested by the chap from Baader) - no difference I have tried a different filter - a Chroma Green kindly supplied by Bern at Modern Astronomy - no difference (indeed maybe the reflections were a little more obvious - I've posted the Chroma version) I have tried 3 different methods of taking flats: an LED panel; a Gerd Neumann EL panel; and sky flats with a pillowcase I had one camera back to Atik who tried blackening the optical window edges. The chap from Baader also suggested putting a spacer between the camera and the wheel. This started to work. As I added spacers, the lines moved to the outside of the frame. Eventually they went away altogether. I was able to lose the lines at 7mm of spacing on one 383L. I needed 7.5mm of spacing with the other. The spacing does not seem to make the vignetting any significantly worse, so this is a 'fix'. On the other hand if you are considering using an OAG, then being forced to add that 7.5mm could be significant. Am I really the only one having this problem?