LASCO Activity Report for
May 18, 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

Medoc Campaign started on May 16. Since then SOHO is in Telemetry submode 5.
EIT 195 CME watch at half resolution (512x512).

2005/05/17 (Tuesday)

03:06 UT  WS West	Initially bright ragged front. The event fades close to 
			the inner edge of C3. EIT 195 images show ejection of
			material on the WSW Limb from barely behind the disk
			between 02:24 - 03:36 UT.

03:50 UT  HALO  	Extremely faint and diffuse brightening all around the
			occulting disk (though not very clear at this time).
			Please note that since 03:06 UT an (initially) bright
			ragged front was seen above the WSW Limb, fading out 
			then close to the inner edge of C3. This particular
			feature corresponds to ejection of material seen by 
			EIT 195 on the WSW Limb from barely behind the disk
			between 02:24 - 03:36 UT and should not be confused 
			with the main event. Coming back to the halo event... 
			the event in itself is so faint that is barely
			discernible in C3, where one can say that it is first
			discerned at around 08:18 UT. A very rough estimation 
			of the mean plane-of-sky speed of the LE of the event
			based on C2 data (where at least it is possible to
			measure something) is ~ 300 km/sec (at PA 211). GOES
			reported an M1.8 X-ray flare from NOAA AR 10763 
			(S15W00) between 02:31 - 02:52 UT with peak emission 
			at 02:39 UT. EIT 195 images show a strong brightening 
			at 02:36 UT on the aforementioned AR. A clear wave is
			seen then developing toward N, W, S, and SE of the AR
			between 02:48 - 03:36 UT. Also a dimming region to N 
			and S of the AR. The AR continued flaring afterward 
			(at the time of writing: a C8.4 peaking at 04:03 UT,
			and a C2.8 peaking at 05:53 UT). In summary, the event
			has therefore been determined as a very faint Full
			Halo CME, frontsided, associated with an M-class X-ray
			flare on NOAA AR 10763.

07:27 UT  ES East	Small loop front along streamer. It fades throughout 
			C2.

12:26 UT  W Limb	Diffuse and very asymmetric loop front that fades
			close to the inner edge of C3. It is followed at ~
			15:50 UT by a very faint ragged front on WNW that 
			fades throughout C3. Gusty outflow.

21:26 UT  ES East	Diffuse and very faint loop front. It fades throughout
			C2.

2005/05/18 (Wednesday)

00:26 UT  S East	Very faint and diffuse expanding loop front. It fades
			throughout C3.

02:06 UT  S West	Bright and ragged loop front. Infalling features in 
			the trailing material on WSW. EIT 195 images show a 
			signatures of a big backsided CME above the SW Limb
			starting at around 01:36 UT. 

Time of the last C2 image analized: 12:06 UT