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SPACE WEATHER MICROSATS:
Space shuttle Endeavour returns to Earth tomorrow, July 31st, completing
a successful construction mission to the ISS, but first there is
one more chore to do. Today, the shuttle's crew will release Castor
and Pollux, a pair of 19-inch spherical satellites. The twin
microsats will circle Earth for approximately one year, working
together to reveal how geomagnetic
storms degrade the orbits of satellites. NASA has the full
story.
CHANGES ON JUPITER:
"On July 30, it is evident that there
is rapid evolution of Jupiter's impact debris cloud," reports
amateur astronomer Raffaello Lena of Rome, Italy. "It is becoming
very elongated." A polar projection shows the extent of the
debris:
The changes are caused by turbulence and especially high-altitude
winds in Jupiter's atmosphere. Polar winds blowing 25 m/s and faster
could stretch the cloud all the way around Jupiter's south pole
in the weeks ahead. Whether such a stretched-out cloud will be visible
in small telescopes remains to be seen.
Amateur astronomers are encouraged to continue monitoring. The
cloud is located near Jupiter's System II longitude 210°. For the
predicted times when it will cross the planet's central meridian,
add 2 hours and 6 minutes to Sky and Telescope's predicted
transit times for Jupiter's Great Red Spot. [sky
map]
more images: from
Giovanni Coltro of Pesaro, Italy; from
Romulo Liporaci of Maracaibo, Venezuela; from
Sid Leach of Scottsdale, Arizona; from
Tamas Ladanyi of Bakonykoppany, Hungary; from
Efrain Morales Rivera of Aguadilla, Puerto Rico; from
Andreas Murner of Lake Chiemsee, Bavaria, Germany; from
John Chumack of Dayton, Ohio USA
LUNAR TRANSITS:
Catching a spaceship flying in front of the Moon is a rare trick.
Yesterday, Roman Piffl of Bratislava, Slovakia, caught two:
"First, space shuttle Endeavour transited the Moon, followed
a hundred seconds later by the International Space Station,"
says Piffl. Each crossing lasted no more than a fraction of a second,
"but we were able to capture them using a DMK21 video camera
at 60 fps." Piffl was assisted by fellow astronomers Tomáš
Maruška and Miroslav Grnja.
Endeavour and the ISS will be in orbit together for just one more
day. Check the Simple Satellite Tracker for
last-chance flybys.
more images: from
Fox Keri of Marion, Massachusetts; from
Todd Hahn of Sugar Land, Texas; from
Jonathan Sabin of Ellenton, Florida; from
Michael Prokosch of Huntsville, Texas
July
2009 Aurora Gallery
[previous Julys: 2008,
2007, 2006,
2005, 2004,
2003]
2009
Noctilucent Photo Gallery
[previous years: 2008,
2007, 2006,
2005, 2004,
2003]
July
22nd Eclipse Gallery
[previous eclipses: Jan
26, 2009; Aug.
1, 2008; Mar. 19,
2007]
Explore
the Sunspot Cycle
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