I'm getting some strange colored artifacts in my pictures taken with my STXL-16200 with self-guiding filter wheel and Astrodon filters, using my TEC 140 mm refractor. The artifacts are in the light frames so they are not a by product of processing. I suspect the four on the left are internal reflections but don't know from what. My only guess is from the screws and rubber washers that hold the filters in place, because when I reseated the filters, screws, and washers, the shape of the artifacts changed some. Note how the shapes change depending on where they are in the frame - the ones near the center are circular while the ones further away are more oval, with the long side perpendicular to the center. Any ideas on what they are and/or how to get rid of them? The circles show the colored artifacts and the rectangles show the blue diffraction spikes.
Looks like some kind of reflection? Can you post a calibrated FITS frame so I can have a closer look?
Doug, the .fit version of the LRGB file above (without the white circles and squares of course) is at http://eccssw.com/astro/Artifacts/MixLRGB-Hue_1.zip. It's 63 MB. Is that what you asked for? It's the combination of 20 L, 12 R, 12 G, and 12 B calibrated, normalized, and stacked.
Did you notice that all your stars have a little divot taken out of them? Here's a stretched and zoomed-in view: I'm thinking that there are stars in your master dark frame. Maybe a mixup in selecting files???
