This is a copy of a masterflat taken with my Atik 383 l+ osc, firstly i need to seriously clean my optics
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The time is 1.72 secs which gives mw about 30,00 adu
When i use this to clean my stacked image it removes the dust bunnies but introduces a gradient in the lower right hand corner that corresponds to the shadow that appears there. A poorly processed running chicken nebula ( looks more like Woody Woodpecker for those old enough to remember ) shows the result
Am i correct to assume it isn't vignetting but something else, amp glow? shutter?
Any ideas as to the cause?
George