From: "John Beamish" 

http://antwrp.gsfc.nasa.gov/apod/ap070303.html

It's a QuickTime movie

Explanation: A million miles from planet Earth, last weekend the STEREO B
spacecraft found itself in the shadow of the Moon. So, looking toward the
Sun, extreme ultraviolet cameras onboard STEREO B were able to record a
stunning movie of a lunar transit (aka solar eclipse), as the Moon tracked
across the solar disk. Each frame of the movie is a false-color composite
of images made through four different filters that highlight temperature
regimes and structures in the upper solar atmosphere. In this frame, large
bright active regions, seen as dark sunspots in visible light, flank the
Moon's silhouetted disk. The Moon appears small, less than 1/4th the size
seen from Earth, because the spacecraft-Moon separation is over four times
the Earth-Moon distance. Tonight, the Moon will find itself in planet
Earth's shadow in a total lunar eclipse.

--- BBBS/NT v4.01 Flag-5