|
CORONAL MASS EJECTION:
In addition to the many prominences on display
around the sun today (see below), another form of solar activity
has appeared. The Solar and Heliospheric Observatory is tracking
a massive coronal mass ejection (CME) billowing away from the sun's
western limb: movie.
The slow-moving cloud will not hit Earth.
SOLAR ACTIVITY:
"Solar minimum? No problem," reports Marco Vidovic of
Stojnci, Slovenia. "Lately, every time I point my telescope
at the edge of the sun, I see plenty of activity." He took
this picture yesterday:
Vidovic uses a telescope equipped with an H-alpha
filter tuned to the red glow of solar hydrogen. H-alpha filters
are ideal for catching prominences--towering plumes of hydrogen
held aloft by the sun's magnetic field. Because prominences are
not rooted in sunspots, they do not vanish when the sunspot count
plunges to zero.
Far from zero, the prominence count today is seven.
Readers, if you have an H-alpha
telescope, take a look at the solar activity that won't go away.
more images: from
Ali and John Stetson of South Portland, Maine; from
Cai-Uso Wohler of Bispingen, Germany; from
Matthias Juergens of Gnevsdorf, Germany; from
Stephen Ames of Hodgenville, Kentucky
COMET Yi-SWAN:
It's up all night long. Northern circumpolar Comet Yi-SWAN is gliding
through the constellation Cassiopeia where it can be seen at almost
any hour of the night through amateur
telescopes. Working at his backyard observatory in Ellisville,
Missouri, Gregg Ruppel took this picture on April 9th:
At the moment, the green, fuzzy comet is about as
bright as an 8th-magnitude star--too dim for the naked eye. If predictions
are correct, it will remain a telescopic comet, brightening only
a little as it approaches the sun for a 190 million kilometer not-so-close
encounter on May 8th. Astronomers will get a better look at the
comet in the evenings ahead as the bright light of the full Moon
fades.
Comet Yi-SWAN was co-discovered by amateur astronomers
Dae-am Yi in Korea and Rob Matson in the USA. Yi photographed the
comet himself using a Canon
5D and a 90 mm lens. Matson noticed it in images taken by the
Solar and Heliospheric Observatory's SWAN
sensor. Because of naming traditions (which should probably be modified)
the comet bears SWAN's name, not Matson's.
This appears to be Comet Yi-SWAN's first visit to
the inner solar system. A fresh comet exposed to intense sunlight
for the first time can behave in unexpected ways. Will it grow a
tail, fragment, brighten ... ? Stay tuned for updates.
related links: 3D
orbit, ephemeris
Explore
the Sunspot Cycle
April
2009 Aurora Gallery
[previous Aprils: 2008,
2007, 2006,
2005, 2004,
2003, 2002]
|
