Explanation:
Despina is a tiny moon
of Neptune.
A mere 148 kilometers across,
diminutive Despina was
discovered in 1989, in images from the
Voyager 2 spacecraft
taken during its encounter with the solar system's most
distant gas giant planet.
But looking
through the Voyager 2 data 20 years later, amateur image processor
(and philosophy professor) Ted Stryk discovered something no
one had recognized before -- images that show the shadow of Despina
in transit across Neptune's blue cloud tops.
His composite view of Despina and its shadow is composed of four
archival
frames taken on August 24, 1989, separated by nine minutes.
Despina itself has been artificially brightened to make it easier
to see.
In ancient Greek mythology,
Despina is a daughter of Poseidon
(the Roman god Neptune).
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