Subject: SOHO/LASCO HALO CME 101028

UCMEO 93001 01029 2315/
01028 61248 82130 0782/ 285// 113// 40244
///// ///// ////// ///// ///// /////
99999

PLAIN

SOHO/LASCO observed an asymmetric PARTIAL HALO CME on October 28, 2010.  Event is first seen in 
C2 at 12:48 UT as a faint but defined loop over the southern hemisphere 207 degrees wide
at PA 78 - 285 degrees. A 2nd multiloop system is following the initial front at PA 242 degrees
with consistent velocities and may be associated.  The event is seen in first frame of C3 
at 15:18 UT and tracked out to 21:30 UT at 12.5 Rsun where the event dissipates.
 
Time/height measurements were marked to 9 points in C2 with speeds of 254.5 km/sec, the event
accelerates in C3, marked at 17 points and calculated to velocities averaging thru both fields
to 272.0 Km/sec at position angle 191 degrees.    

STEREO EUVI Ahead beacon data shows a long filament channel in it's South West quadrant
which extends between the South coronal region and AR 11112 on Aheads west limb area.
The beacon data has an outage between 06:55 - 11:15 UT.  There is no positive evidence 
of an eruption shown in the EUVI images. SDO AIA and EUVI Behind show no activity.  
A filament eruption and a filaments characteristics is the likely cause of the type 
of event seen in LASCO.  There were no Earthward facing events or activity.
   
The observation of this event in LASCO is considered 'good'. This CME is determined a BACKSIDE event. 

Images and movies and time/height information for this event is available on the web at:

http://umbra.nascom.nasa.gov/lasco/observations/halo/2010/101028/

Best regards,

Kevin Schenk
Solar Heliospheric Observatory (SOHO)
EIT and LASCO Operations
NASA-Goddard Space Flight Center, USA

BT