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.
