The Astronomical Society of Eastern Missouri is the public outreach activity of the Alliance for Astronomy, Inc., a Missouri non-profit corporation. The mission of Alliance is
to promote public awareness, appreciation and education in astronomy and related sciences.
I was recently reminded of this object and I thought of this image I
made years ago. It is an animated gif that shows the effect when two
pictures about 3 hours apart are superimposed. (If it doesn't blink in
your browser, try clicking on it.)