Earth Rotating Under Very Large Telescopes
Why is the Earth moving in the above video?
Most time lapse videos of the night
sky show the stars and sky
moving above a steady Earth.
Here, however,
the frames have been digitally rotated so that it is the stars that stay (approximately) steady, and the Earth that moves beneath them.
The video dramatically shows the actual rotation of the Earth, called
diurnal motion,
in a clear and moving way, as if the camera were
floating free in space.
The
telescopes featured in the video are the
Very Large Telescopes (VLT) in
Chile,
a group of four of the
largest optical telescopes
deployed anywhere in the world.
A discerning observer of the
above time lapse movie may also note the use of
laser guide stars,
zodiacal light, the
Large and
Small Magellanic
Clouds, and fast-moving, sunlight-reflecting,
Earth-orbiting satellites.
The original video, on which the above sequences are based, can be found
here.
