[X] My Assistant

[garybeau]

What's this mark in the sky of this image. It looks to well defined to be dust or dirt on the lens or filter. It doesn't look like a jpeg compression artifact or a drop out
of data. I don't see it in any subsequent images. Any ideas? Have we seen something like this in other images?

http://qt.exploratorium.edu/mars/spirit/pa...03P2264R7M1.JPG

[Jeff7]

There WAS a pic of a similar, though considerably brighter, artifact of the same shape in this thread, but the image is gone now, as the thread is fairly old.
Look close to the left of the darkest dot and line - there's something faintly resembling a sword there. The image that was in the above thread had a similar thing, only it manifested itself very brightly.