M98 puzzle

Someone directed me to a puzzle, so I thought I would pass it along. I have my own ideas, so don't want to influence. Especially if someone already knows the "right" answer. (Since he asked me if this was an asteroid, I guess I should throw that question in.)

He sent me the attached image from some "newer" sky viewing product. Apparently there is a dark blob near M98 that doesn't show up in most images. Turns out to be scans from the POSS I survey. The link they sent to a more original had a good negative image, so just look up M98 here.

http://aps.umn.edu/catalog/skybox

So what are your thoughts on what the dark spot could be, and why?

Charlie

Attached Image:

Oh, I really don't know. But my guess is a dust mote based on gut feel.

Hi Charles,

Black Hole? ....Nah, just kidding! It just shows up on the POSS1 red image. It's most likely a plate defect ... it's pretty common. It could also be a piece of dirt or "grunge" in the optical system or on the plate. I get little "black holes", all the time in my images, from "grunge" on a filter or on the chip.

Jim