Explanation:
Despite their resemblance to
R2D2,
these three are not the droids you're looking for.
Instead, the enclosures house 1.8 meter
Auxiliary Telescopes
(ATs) at Paranal Observatory in the Atacama Desert region of Chile.
The ATs are designed to be used
for
interferometry,
a technique for achieving extremely high resolution observations,
in concert with
the observatory's 8 meter
Very Large Telescope units.
A total of four ATs are operational, each
fitted with a transporter
that moves the telescope along
a track allowing different arrays with the large unit
telescopes.
To work as an interferometer, the light from each telescope
is then brought to a common focal point by a system
of mirrors in underground tunnels.
Above these three ATs, the Large and Small
Magellanic Clouds
are the far far away satellite galaxies of our own Milky Way.
In the clear and otherwise dark southern skies,
planet Earth's greenish atmospheric
airglow stretches faintly
along the horizon.
