The Telescope of Bits
June 16, 2011
Via the indispensable Jason Kottke, a mesmerizing movie of the moon’s annual wobble-and-wink:
Here’s the thing about this movie: it’s an animation. The Goddard Space Flight Center’s visualization studio combined laser altimeter measurements made by the Lunar Reconnaissance Orbiter to map the lunar topography with unprecedented precision, and then used software to model the moon’s phases and its wobble in the night sky — the latter a complicated dance of perigee and apogee, orbital path and declination. As the moon follows its course around the Earth, our vantage shifts, and we catch glimpses of framing slices of the lunar surface around the edges of its earthward face. This wobble is called libration, after the Latin libra for balance or scale — another example of astronomy’s ancient dalliance with the gods and spirits of the Mediterranean.
While it’s not a photographic image, this animation is drawn from nature in a very particular way. It’s a portrait made of captured bits, lifted from the lunar surface like a filmy fingerprint, sluiced through precisely gated circuits, flung across the transorbital gulf between Earth and its satellite. The computers that rendered it are far-seeing machines — telescopes in the precise sense of the word, extending our vision as surely as the hand-ground lenses of Galileo, by which he first realized the face of the moon was made not of some pure and shining substance, but of terrain. These images may be made digitally and not optically, but the distinction becomes one of style not substance; the eyes are still are own.