Subject: SOHO/LASCO Partial HALO CME 120922 BACKSIDED

UCMEO 93001 20924 2030/
20922 60324 81042 3142/ 176// 323// 41051
20922 60255 8345 ///// ///// 1122/
99999

PLAIN

SOHO/LASCO observed a partial HALO CME on September 22, 2012.  Event is first seen
in C2 at 03:24 UT as a compressed loop with cavity and core over the East limb.
The event expands with extensions PA 314 - 176 degrees for a total width of 222
degrees wide. The event continues into the C3 field beginning 03:42 to 10:42 UT
leaving the C3 field at 30 Rsun in the East.

Time/height measurements were marked to 3 points in C2 with speeds 
of 1226.3 Km/sec at position angle 98 degrees. The event is marked to 10 points 
in C3. Speeds average through both fields to 1051.1 Km/sec at PA 97 degrees.  
Acceleration -18.84 m/sec^2.

SDO/AIA : n/a

STEREO: Beacon and HR data
COR2 B, 03:54 UT a faint symmetric halo.
Preliminary time/height measure gives 671.1 km/sec velocity at LE.
EUVI B, 02:56-03:16 UT still in progress before data gap at 03:16 UT.  The
AR located on disk at [S18, E-128].
COR2 A, 03:24 UT loop expanding over the SW, develops a full halo by 05:54 UT
Preliminary time/height measure gives 1123.9 km/sec velocity at LE.
EUVI A, 195A shows a flare with CME and wave from region behind limb in SW. 

The observation of this event is considered 'GOOD'. 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/2012/120922/

Best regards,

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

BT