Quoting Joe Bauman <bau@desnews.com>:
Hi all, When I checked out the Sky & Telescope web site below (from Patrick's News), it had a great animation of the moon occulting Jupiter, on the third page. What I can't understand is why Jupiter is in sharp focus while the moonscape is slightly fuzzy. It isn't possible that there could be a real difference in focus between the two, I believe -- granted, Jupiter is thousands of times farther out, but for all practical purposes the focus for both should be at infinity.
Joe, I took a college astronomy class believe it or not, and I didn't learn anything. I was too busy throwing spit wads in class... ;) from my corner perch, I do remember hearing a discussion which may have a bearing on your question. The theory regarding the curvature of space and time was proved, was proven, arrrggghh, was 'confirmed', during a solar eclipse, where a visible star's position had changed when it was near the edge of the eclipsed sun. This curvature of space around objects may explain why one object, Jupiter, is in focus and one, the moon, is slightly blurred. I know that if I hold my thumb up in front of my eye and move my thumb towards this letter "A", the view of the letter "A" becomes real sharp as I near the edge. Perhaps this is similar to what is happening with the moon and Jupiter, but on a smaller scale. You know if I were to use both thumbs and both eyes, hey, I would have perfect vision. Of course I would look pretty silly trying to operate a vehicle using my elbows... ;) Guy