Be sure that when trying to see an aura that you stare at one spot and do not move your eyes. if you see something out of the edge of your eye, it is then not an afterimage but an aura, because the after image is the exact size of the image while the aura is bigger.
This much I know, but more I cannot say because I have yet to see one myself.
This much I know, but more I cannot say because I have yet to see one myself.