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Post Info TOPIC: Sun 03.08.06


L

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RE: Sun 03.08.06
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Once a year Saturn and Earth find themselves almost directly opposite each other with the Sun in between, an event called conjunction. This year, conjunction will occur on August 7.
As Saturn nears the Sun, radio communications with the Cassini spaceprobe get very noisy, so most of Cassini's science operations are temporarily suspended.
The last high-rate science data playback, at 14,220 bits per second, will occur August 4, after which Cassini switches to low-rate telemetry downlink, at 1896 bps.

During conjunction, the mission switches gears.

"Finally, a break. We know the spacecraft is safe, especially since it won't be doing lots of commanded science activities, instead just staring at Earth with its high gain antenna. We'll be carrying out radio science studies of the solar corona, using carrier signals coming down from Cassini to study the sun's extended, super-hot atmosphere. Meanwhile, the spacecraft team's radio communications engineers will watch how many out of 100 test commands sent each day are received aboard the spacecraft with the noisy Sun in the way. We'll also be using this low-activity period to conduct an operational readiness test, realistic training using contrived problems, for many of the new members of the flight team" - David Doody, Cassini flight operations lead.

Cassini will resume returning high-rate science data on August 10, when it is well past the Sun.

Saturn will be visible again to the unaided eye about two weeks after conjunction. On the morning of August 20, Saturn will rise in the east an hour before the sun does. Early birds in the United States will be able to spot swift Mercury one degree above Saturn. The next morning, they can spot Mercury one degree to the lower left of the planet. On August 26 and 27 Saturn pairs with much brighter Venus.

Source JPL

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L

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Saturn is passing by the sun this week.

Sun 030806

This coronagraph image from the SOHO spacecraft shows the planet as a bright dot in the constellation of Cancer.



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