For the second day in a row, I’m taking my cue from Astronomy Picture of the Day (APOD). What a way to start the new year. But instead of light from the early history of the Universe, in the above image we’re looking at light from about a second and a half ago.
APOD actually presents an image similar to the one above, which includes grid lines that make the changing size of the Moon easier to discern. What’s almost impossible to see, however, is the slight nodding of the Moon (its libration) over the period of a year. As I looked at the APOD image, I immediately thought, “This would be much better as an animation!” And indeed, the images above (and the ones featured on APOD) have been assembled into both an animated GIF and a Flash animation. Kewl! I’ve seen simulations of the Moon’s libration, but seeing actual photographs assembled in this way creates a stronger impression.
(I chose this sequence over the APOD version not just because I’m perverse but because it shows one full revolution of the Moon, rather than a revolution-and-a-half. I find it easier to watch when it baically goes through an approximate single cycle then repeats.)