Explanation:
Every 14 to 15 years, Saturn's rings
are tilted
edge-on to our line of sight.
As the bright, beautiful rings seem to grow narrower
it becomes increasingly
difficult to see them, even with large telescopes.
But it does provide the opportunity to watch multiple
transits of Saturn's moons.
During a transit, a sunlit moon and its shadow
glide across the cloudy face of the gas giant.
Recorded on February 24,
this
Hubble image is part of a
sequence
showing the transit of four of Saturn's moons.
From left to right are Enceladus
and shadow,
Dione
and shadow, and
Saturn's largest moon Titan.
Small moon Mimas is just
touching Saturn's disk near the
ring plane at the far right.
The shadows of Titan and Mimas have both moved off
the right side of the disk.
Saturn itself
has an equatorial diameter of about 120,000 kilometers.
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