Moving spot

• by gasta_berserkr

  There's a light grey spot that moves randomly across the frames. I signalled it as an artifact, but it doesn't match the artifact types on the Guide, if I'm not mistaken. I wondered what kind of artifact that might be.

  Posted January 10, 2015 1:41 AM

• by grums

  There are various spots (small and bright) or dark areas or like the grey area you have here. They are due to a local issue with the CCD detector array (cosmic ray hit or some other local effect). The detector array is shifted on each image so that these effects can be seen as a moving mark and identified as an artifact. Anything that moves in a shape that resembles a slightly sloping inverted crucifix is due to this. You will see this effect on a lot of image sets. Sequence frame to frame is bottom, top, right, left (or something similar) but always the same.

  Posted January 10, 2015 9:39 AM