SOHO/LASCO Partial HALO CME 120416 UCMEO 93001 20417 0220/ 20416 61748 82130 3283/ 146// 328// 41452 20416 61725 81812 17512 ///// 1112/ 99999 PLAIN SOHO/LASCO observed a partial HALO CME on April 16, 2012. Event is first seen in C2 at 17:48 UT as a bright burst off the east. The approximate width of the CME spans pa 328-146 degrees totaling 178 degrees wide. The event continues into the C3 field beginning 17:54-21:30 UT to the edge of the field in the east. Time/height measurements were marked at 2 points in C2 with speeds of 2077.2 Km/sec at position angle 90 degrees. The event is marked to 11 points in C3. Speeds average through both fields to 1452.1 Km/sec at PA 88 degrees. Acceleration of -92.29 m/sec^2. SDO AIA 193 shows ejecta from an AR coming on disk with flare in the east located [N12,E77] beginning 17:27-18:12 UT with a small wave southward along the limb. AIA 304 shows elevation of a large loop of cooler material near AR in the east. A flare of the AR blows out the expanding loop, inflow is seen. STEREO: Beacon data COR2 B, 17:54 UT, a loop on the west. Asymmetric halo west by 20:24 UT. Preliminary time/height measure gives 1247.9 km/sec velocity at LE. EUVI B, 17:25 UT activated filament which lies between 2 AR in the NW. At next frame 17:35-18:45, a flare of the AR to the right of the filament with cme. Event produces a dimming south and a wave south and southeast of the AR(s). COR2 A, 18:24 UT symmetric halo from first frame. Preliminary time/height measure gives 671.3 km/sec velocity at LE. EUVI A, n/a NOAA reports a M1.7 Xray flare 17:24-18:00 UT from AR on the east limb located [N12,E77] The observation of this event is considered 'GOOD'. This CME is determined a LIMB event. Material seems to be spread across both sides of the East limb area as shown from EUVI and COR2 BEHIND. Images and movies and time/height information for this event is available on the web at: http://umbra.nascom.nasa.gov/lasco/observations/halo/2012/120416/ Best regards, Kevin Schenk Solar Heliospheric Observatory EIT and LASCO Operations NASA-Goddard Space Flight Center, USA BT