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Астронет: Астрономическая картинка дня Диона и Рея проходят перед кольцами http://www.astronet.ru/db/msg/1984417/eng |
Credit & Copyright: Christopher Go
Explanation:
Seen to the left of Saturn's banded planetary disk, small icy moons
Dione
and
Rhea
are caught passing in front of the gas giant's
extensive ring system
in this sharp telescopic snapshot.
The remarkable image was
recorded on November 20,
when Saturn's rings were nearly edge-on when viewed from planet Earth.
In fact, every 13 to 16 years the view from planet Earth
aligns with Saturn's ring plane to produce a series of
ring
plane crossings.
During a ring plane crossing, the interplanetary
edge-on perspective
makes the thin but otherwise bright rings seem to disappear.
By
November 23rd
Saturn's rings will have reached a minimum angle for now,
at
their narrowest
for viewing from planet Earth, but then start to widen again.
Of course, Dione and Rhea
orbit Saturn
near the ring plane once every 2.7 and 4.5 days
respectively, while the next series of Saturn ring plane crossings
as seen from Earth will begin again in 2038.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.