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Science Forum Index » Astro - Amateur Forum » Jupiter - GRS changes
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| canopus56 |
 Posted: Tue Apr 29, 2008 1:18 pm |
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Rogers, JOhn H. Feb. 2008. The accelerating circulation of Jupiter's
Great Red Spot. J. Br. Astron. Assoc. 118(1):14-20
http://www.britastro.org/journal/118-1.htm
Summarized and abstracted from the above article.
Since about 1949, the characteristics of the GRS changed as follows:
1) Length: ~28 degs to 16-18 degs, the smallest ever recorded. 1 deg
= 1160km.
2) Circulation period of vortex within GRS: 12 to 4.5 days
3) Wind speeds as measured by amateur CCD and spacecraft imaging of
streaks and spots within the GRS:
1979 Voyager 1 110-135 m/s
1979 Voyager 2 110 m/s
1996 Galileo 115-135 m/s
2000 Galileo 145-165 m/s
ALPO 2001-2002 100 +-8 m/s
ALPO 2002-2003 89-97 m/s
BAA 2006 112 m/s (this paper)
100 meters per second equals 360 kilometers per hour
After its initial report as Cassini's Spot (1615), the Great Red Spot
may have dissolved and reformed during the 1700s. The GRS was not
reported again until the 1800s.
The position of the GRS slightly oscillates (less than 1 deg) in both
latitude and longitude on a 90 day period.
For North America, Jupiter is low in the southeast in Sagittarius
about 1 1/2 hours before sunrise. Jupiter's position in the ecliptic
means that it will not be possible to due high altitude imaging of
this planet for several years.
An animating web cam video opportunity of the reappearance of Callisto
from Jupiter's shadow, more than one Jupiter diameter of Jupiter from
its disk, exists for the Intermountain West of the U.S. on May 5, 2008
at 4:12am MDT (10:12 UT). Jupiter will have two visible moons, then
Callisto will pop into view some distance from the planet's disk.
Details are available in Table 1 at:
http://members.csolutions.net/fisherka/astronote/tours/JMEcl2008/JupEclSP.html
- Canopus56 |
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