On the fourth plate there's an interesting object that looks like a distant galaxy with spiral arms. Trick of the camera?
Lizzie, yes it looks like a #galaxy, and shows up slightly in 3, very faint in2, and does not move between images. That's the best indicator it is a real object in space. The black shapes in the bottom right of 4 are likely a big flat field defect #ffd , and would shift positions between images.
i did a quick search for you, the galaxy is NGC 5829. Its to the left of the constalation bootes.
My post http://talk.asteroidzoo.org/#/boards/BAZ0000001/discussions/DAZ0000853 shows you how to do the searches for objects and what they are.