Explanation:
Jupiter is
an astronomer's planet --
its large size and contrasting global
cloud belts and zones
allow detailed studies with a range of
earthbound telescopes.
On the other hand, most telescopic views
of Jupiter's moons usually
show only featureless, tantalizing points of light hovering near
the ruling gas giant.
But this impressive picture from a small, ground-based
telescope reveals a
stunning
amount of detail on Ganymede,
a jovian moon about the same size as Earth's moon but at least 1,500
times farther away.
The image was carefully constructed by combining and processing
only the 409 sharpest frames from a total of 10,000 recorded
at 30 frames per second by a digital camera.
Ganymede's
radius is about 2,600 kilometers indicating that the
surface markings visible are as small
as around 900 kilometers across.
