Date: Fri, 30 Apr 2004 10:22
From: Guillermo Stenborg
Subject: 'Full' halo CME on 2004/04/29, backsided
UCMEO 93001 40430 1625/
40429 61927 80642 0002/ 360// 113// 20197
///// ///// ///// ///// ///// /////
99999
PLAIN
BT
LASCO observed a 'full' halo CME on 2004/04/29. The event was
first observed in C2 at 19:27 UT as a ragged loop front above
the SW limb, followed at 21:26 UT by a couple of wide loop
fronts developing toward SE. By that time a front begins to be
visible above NW. The resulting complex event becomes a 'full'
halo CME as seen in C2 FOV by 23:06 UT, though extremely faint
above the W Limb. The event becomes a 'full' halo in C3 by
01:42 UT on 2004/04/30. By 06:42 UT it becomes so faint that
is no longer discernible in the C3 FOV. For reference, the
mean plane-of-sky speed at different PA as obtained from C2
and C3 measurements is given below, showing in all cases slight
deceleration:
PA 209 : 197 km/s
PA 117 : 187 km/s
PA 342 : 172 km/s
EIT Fe XII shows no signatures of the event. Likewise, there
is no report of a flare by the time. Therefore, the complex
event has been determined as most probably backsided.
Movies and images of the event will shortly be available at:
ftp://ares.nrl.navy.mil/pub/lasco/halo/20040429
Best wishes,
Guillermo Stenborg
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Dr. Guillermo A. Stenborg
SOHO-LASCO Operations Scientist,
CUA, MC 682.3, Bldg 26, Rm 001, F: +1-301-286-0264
NASA Goddard Space Flight Center,
Greenbelt, MD 20771. P: +1-301-286-2941
e-mail: stenborg@kreutz.nascom.nasa.gov
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