Subject: SOHO/LASCO Partial HALO CME 120623 BACKSIDED

UCMEO 93001 20626 1930/
20623 60712 81206 2052/ 078// 333// 41349
20623 60633 80721 ///// 11506 2112/
99999

PLAIN

SOHO/LASCO observed a partial HALO CME on June 23, 2012.  Event is first seen
in C2 at 07:12 UT as a bright loop with cavity and core over the Northwest limb.
The event expands with extensions PA 205 - 78 degrees for a total width of 233
degrees wide. The event continues into the C3 field beginning 07:42 to 12:06 UT
leaving the C3 field at 30 Rsun in the Northwest.

Time/height measurements were marked to 4 points in C2 with speeds 
of 1211.1 Km/sec at position angle 297 degrees. The event is marked to 6 points 
in C3. Speeds average through both fields to 1349.0 Km/sec at PA 298 degrees.  
Acceleration 59.39 m/sec^2.

SDO/AIA 193 shows elevated prominence material beginning 05:07 UT over the NW.
At 06:30 UT eruption begins with ejecta and a wide wave of material backside.
A long duration post loop arcade is seen over the limb 07:54-10:39 UT.

STEREO: HR data
COR2 B, 07:39 UT a faint loop over the NE which develops a full halo by 08:39 UT.
Preliminary time/height measure gives 1000.7 km/sec velocity at LE.
EUVI B, 07:05-08:20 UT cme emission over NE behind limb, eastward projection.
COR2 A, 07:39 UT bright loop over NE with fainter emission developing to a
full halo by 08:24 UT.
Preliminary time/height measure gives 1174.0 km/sec velocity at LE.
EUVI A, 195A shows 06:30 UT activation of a filament near AR 11506 in NE.  Eruption
of the region begins 07:00-07:35 UT with a large wave and post arcade.
EUVI 304A shows activated filament eruption with eastward ejecta by 07:21 UT. At 
08:48 UT-11:26 UT a second wave of filament material erupts west of and adjacent 
to AR 11506.

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/2012/120623/

Best regards,

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

BT