The two photos above were taken consecutively (a 30-minute shot, followed by a 40 minute shot). During this time, the comet moved very slightly at this image scale. Reminded by the recent S&T article on Akira Inaka's 3D constellation shots, I decided to try to arrange these shots for a 3D view of the comet.
If you've never tried 3D viewing, the idea is to "cross" your eyes so that the two panels above become a panel of three images, with the center one appearing as the 3D image. If you have difficulty understanding that, try holding your finger up between your eyes and the images on your screen. At some distance, with your finger in focus and the photos in the background, you will see the apparent third center photo form. Now try focusing on the middle photo. The comet should seem slightly raised above the photo while the stars remain flat on the surface.