LASCO Activity Report for
May 18, 2004 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

LASCO will be participating with the coronal holes/streamer boundary study 
of UVCS/SUMER/CDS during May 17th through 23rd. It introduces only slight
modifications to the LASCO synoptic observation plan:

For C2: 6 hr cadence in orange filter pB (02:54 - 08:54 - 14:45 - 20:54 UT)
For C3: 12 hr cadence in orange filter pB (10:42 - 22:42 UT)


SOHO Telemetry Submode changed to Submode 5 on 2004/04/13 at 16:00 UT 
(SUMER began observing on 2004/04/14). SUMER campaign runs until 2004/06/17.
In other words, LASCO synoptic observation plan cadence remains the same
but the EIT CME watch images will be reduced to half-resolution (512x512)
during that period.

2004/05/17 (Monday)

05:26 UT  W Limb	Bright ragged loop front and trailing material. It fades
			throughout C3. In C2, a very faint and diffuse envelope
			surrounds the front. CME signature in EIT Fe XII 
			starting between 04:12 - 04:24 UT right on W Limb.

05:50 UT  N East	Kind of 'reconexion' event. Structure flowing out and
			another one falling down. Separation point at ~ 3.8
			solar radii (PA ~ 55 deg).
		
06:50 UT  S East	Fast narrow and ragged (diffuse) loop front. It fades
			throughout C3.

11:50 UT  W Limb	Faint ragged loop front in the trailing material of 
			event reported to start at 05:26 UT. By that time, 
			the slow development of a twisted structure can be 
			seen in C2 superposed in the LOS. Difficult to separate
			the events.

13:27 UT  ES East	Bright front with asymmetric faint extensions to N and 
			S. The extensions are barely visible in C3. Backsided
			CME signatures in EIT Fe XII running difference images
			startint at ~11:48 UT on ESE Limb.
			
15:26 UT  S West	Wide asymmetric loop front. Difficult to give an exact
			time of first appearance. By 22:06 UT, a more symmetric 
			loop develops within the previous asymmetric loop, 
			while at roughly the PA of its northern leg an 
			apparently faster front seems to develop (not clear
			in C3). No signatures of the event seen on the disk in
			EIT Fe XII images.

18:26 UT  E Limb	Bright and relatively narrow front with faint extensions
			to N and S. It fades throughout C3.

2004/05/18 (Tuesday)

	07:20 - 12:05 UT	Temporary DSN Data Gap.