Subject: SOHO/LASCO Partial HALO CME 120304a BACKSIDED

UCMEO 93001 20306 1930/
20304 60648 81042 2422/ 043// 113// 40526
20304 60546 80646 ///// 11422 1112/
99999

PLAIN

SOHO/LASCO observed two (2) HALO CMEs on March 4, 2012.  The first event is 
first seen in C2 at 06:48 UT as a faint loop over the North hemisphere. 
The loop expands from position angle 242 to 43 degrees for a total width of 161
degrees.  The event continues into the C3 field beginning 07:18 to 10:42 UT
out to 15.0 Rsun where the event dissipates in the north.

Time/height measurements were marked to 6 points in C2 with speeds of 501.9 Km/sec
at position angle 328 degrees. The event is marked to 4 points in C3. Speeds average
through both fields to 526.0 Km/sec at PA 327 degrees.  Acceleration 24.57 m/sec^s.


SDO/AIA n/a 

STEREO: Beacon data
COR2 B,  Beginning 06:25 UT with a burst from the East and scattered material
in the north.  These are separate events but timings are close.
Preliminary time/height measure gives 542.0 km/sec velocity at LE. 
EUVI B, 05:46-06:46 UT flare with CME from AR (11422?) on E limb small wave
along limb.  A dimming in a region near the NCH shows release. 
COR2 A, Beginning 06:54 UT a wide loop over the North and Northwest.
Preliminary time/height measure gives 484.4 km/sec velocity at LE.
EUVI A, 06:05-06:45 UT data gap.  At 05:55-06:55 UT a CME is seen from the flare
of AR (11422?) in the NW along with a liftoff of a filament adjacent to east edge
of the AR.

   
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/2012/120304a/

Best regards,

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

BT