May 12-14: IPS Measurements. During the IPS study, EIT will have regular synoptics along with half resolution 195 CME watch. On 2005/05/03 @ 19:06 UT SOHO Telemetry Submode changed to Submode 6. It will be in Submode 6 until 2005/05/16 @ 12:00 UT. During that time, EIT 195 CME watch at full resolution (1024x1024).
01:31 UT WN West Bright ragged front in the trailing material of event reported to start at 19:31 UT on previous day. 07:31 UT S West Big ragged loop front. By 08:30 UT a not-well- defined front develops a little bit to N, on WNW. Some expanding loop fronts can be seen in the trailing material afterward. GOES reported an M1.2 X-ray flare from NOAA AR 10758 (S11W45) between 06:11 - 06:56 UT with peak emission at 06:41 UT. 17:00 - 19:30 UT EIT Shutterless Campign, Segment #2 (No LASCO images during that time) 20:13 UT S West Bright ragged loop front that later develops as a Full Halo CME. Note that already in previous frame, i.e. at 19:42 UT, a very small brightening can already be discerned. Diffuse extensions surround completely the C2 occulting disk by 21:05 UT. The event was first seen in C3 at 20:40 UT appearing above the SW Limb. The diffuse (almost) circular extensions are first seen in next frame, at 21:34 UT. By 22:22 UT the C3 occulting disk is well covered. The mean plane-of-sky speed of the LE of the event (based on C3 data) at PA 231 was ~ 470 km/sec, showing an slight deceleration. GOES reported an M1.1 X-ray flare on NOAA AR 10758 (S11W51) between 19:22 - 19:55 UT with peak emission at 19:38 UT. EIT was in Segment #2 of a Shutterless Campaign, between 17:00 - 19:30 UT, and therefore only subframes (in 195 A) were taken during that time with a cadence of about 1 image per minute. Fortunately, the subframes were centered on AR 10758. Running difference of these images show a strong brightening starting at around 19:21 UT. By 19:24 UT, a ragged structure starts to lift off toward SW. EIT 195 CME watch images resumed at 19:51 UT. An intensity disturbance traveling mainly toward S and SE of the AR is seen by the time. In summary, the event has therefore been determined as a Full Halo CME, frontsided, associated with an M-class X-ray flare on NOAA AR 10758.
06:22 - 11:22 UT Temporary Data Gap.