LASCO Activity Report for
May 12, 2005 SOHO Science Daily Meeting

Event times are first frame seen in C2 camera unless otherwise noted.
These are preliminary observations for the daily SOHO science discussions.
Final analysis is reported on the Lasco CME list.
An archive of these reports is available.

Points Of Interest

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).

2005/05/11 (Wednesday)

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.

2005/05/12 (Thursday)

	06:22 - 11:22 UT	Temporary Data Gap.