Subject: SOHO/LASCO HALO CME 120711 BACKSIDED

UCMEO 93001 20716 1800/
20711 60125 80642 1102/ 109// 113// 30380
20710 62345 80035 ///// ///// 1122/
99999

PLAIN

SOHO/LASCO observed a full HALO CME on July 11, 2012.  Event is
first seen in C2 at 01:25 UT as a faint asymmetric halo (east).
The event continues into the C3 field beginning 01:54 to 06:42 UT
as the cme dissipates in C3 at approximately 20 Rsun.

Time/height measurements were marked to 9 points in C2 with speeds 
of 344.4 Km/sec at position angle 110 degrees. The event is marked to 5 points 
in C3. Speeds average through both fields to 379.6 Km/sec at PA 110 degrees.  
Acceleration 36.62 m/sec^2.

SDO/AIA:  n/a 

STEREO: Beacon data
COR2 A, 22:24-01:24 UT data gap. 01:24-04:39  UT as a bright loop expanding
over west hemisphere.
Preliminary time/height measure gives 645.6 km/sec velocity at LE. 
EUVI A, 22:15-01:15 UT data gap. n/a.
COR2 B, 00:54-04:39 UT, expanding burst over the east hemisphere.
Preliminary time/height measure gives 468.5 km/sec velocity at LE. 
EUVI B, 23:45-00:35 UT, a cme on SE limb with wave.

   
The observation of this event is considered 'FAIR'. This CME is determined a BACKSIDED 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/2012/120711

Best regards,

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

BT