SOHO/LASCO Partial HALO CME 120405 UCMEO 93001 20406 1620/ 20405 62125 80506 1971/ 019// 333// 30898 20405 62021 82154 43421 11450 2112/ 99999 PLAIN SOHO/LASCO observed a partial HALO CME on April 5, 2012. Event is first seen in C2 at 21:25 UT as a bright loop front over the west. The approximate width of the CME spans pa 197-19 degrees totaling 182 degrees wide. The event continues into the C3 field beginning 21:54-05:06 UT to the edge of the field in the NW. There is a small increase of proton particles seen in the white light images. Time/height measurements were marked at 5 points in C2 with speeds of 813.2 Km/sec at position angle 310 degrees. The event is marked to 9 points in C3. Speeds average through both fields to 897.9 Km/sec at PA 312 degrees. Acceleration of 24.12 m/sec^2. SDO AIA 193 shows a cme from AR 11450 with a flare located [N18,W29] beginning 20:57-21:54 UT with dimming and small wave west of the AR and bright post arcade. AIA 304 shows a filament elevating/activating adjacent to AR 11450 at the north [N21,W34] beginning 20:21 UT. As the filament erupts a flare of AR 11450 triggers at 20:54 UT in AIA. STEREO: Beacon data COR2 A, 21:54 UT in 1 frame, bright loop cme beginning over the east. 21:54-03:54 UT data gap. EUVI A, 20:45-21:55 UT AR 11450 on limb in NE, cme with small wave. 21:55-03:55 UT gap. COR2 B, 19:54-00:24 UT data gap. at 00:24 UT a partial halo cme over north hemisphere in progress which is close to edge of field at first frame. EUVI A, 20:05-22:55 UT data gap. n/a NOAA reports a long duration C1.5 Xray flare 20:49-21:57 UT from AR11450. The observation of this event is considered 'FAIR'. This CME is determined a FRONTSIDED 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/2012/120405/ Best regards, Kevin Schenk Solar Heliospheric Observatory EIT and LASCO Operations NASA-Goddard Space Flight Center, USA BT