Perhaps, posting during the wee hours is not a good idea. But that's the down side of having a shift worker in the house.
I can't be sure what caused this line through the image. It was taken some time ago with a very poor quality lens - the ghosting is quite apparent. The only reason I kept it was because of this artifact. I've inverted the image to increase the contrast, but what might be the cause? It appears to be a trace of light and only guess it's origin?
Closer examination shows the trace originating in the bottom right of the frame and then it seems to increase in intensity at the top of the image followed by a short diminishing spiral and the trace stops.