Sea Urchin Macro

Indoor photography reigns supreme today on a cold and wet February day. This is a macro of a tiny part of a sea urchin taken with my digital USB microscope. Because the surface of a sea urchin is curved I had to photostack about 6 shots to get a reasonably sharp image overall and even so the tops of the nodules on the urchin are a soft. If I was so inclined I could work out what magnification this is by comparing the shot of a ruler at the same focus point but I have not bothered to do the mathematics