LASCO Activity Report for
August 17, 2006 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

2006/08/16 (Wednesday)

07:31 UT  W Limb	Ragged and diffuse front preceding the development 
			toward SW of a system of wide and expanding (brighter)
 			loop fronts. The outermost front seems to fully cover
 			the C2 occulting disk by 09:08 UT. The signal on the
 			eastern hemisphere is extremely faint and just above 
			the occulting disk, while on W it is already past the
 			outer edge of the C2 FOV. The event is first seen in 
			C3 at 08:18 UT appearing above the SW limb as a 
			diffuse loop front. The brighter system of loops shows
 			up at 10:19 UT. By that time, the outer front fully
 			surround the C3 occulting disk (signal on the eastern
 			hemisphere just above the occulter). The mean
			plane-of-sky speed of the outermost front of the 
			event (very faint and diffuse) at PA 230 was ~ 600
 			km/sec (based on C3 data), showing practically no
 			acceleration. GOES reported prior and during the time 
			of the LASCO event, a couple of impulsive B-class 
			X-ray flares on NOAA AR 10904 on top of B-level X-ray 
			activity: 
			i) a B2.1 (at S11W09) between 04:54 - 05:00 UT with 
			peak at 04:57 UT, and 
			ii) a B3.4 (at S13W16) between 08:12 - 08:19 UT with
	 		peak at 08:15 UT.
			EIT 195 images show the formation of a dimming region 
			to N of AR 10904 starting at 07:13 UT. Between 08:48 -
 			11:46 UT, formation of loops connecting from quiet 
			Sun and AR 10904 to bright plasma NW of AR. At 10:14 
			UT, loops in center of AR open and appear to eject
 			material.

16:30 UT  S Pole	Bright and wide loop front, the LE already half way 
			to the end of the C2 FOV (note that there is a 
			C2/C3/EIT 195 Full Field data gap between around 
			14:30 and 16:30 UT due to EIT/CDS ICAL01
			-Intercalibration for EIT with CDS- between 15:00 -
 			16:20 UT). By 17:30 UT, the LE of the event is already
 			past the outer edge of C2, and diffuse extensions all
 			around the outer edge of the event fully cover the
			occulting disk. The event was first seen in C3 at 
			16:42 UT appearing about the S Pole. By 19:42 UT the 
			C3 occulting disk is fully covered (signal on N just
 			above the occulting disk). The mean plane-of-sky speed
 			of the outermost front of the event (it becomes very
 			diffuse by the end of the C3 FOV) at PA 175 was ~ 
			915 km/sec (based on C3 data), showing a slight 
			acceleration. GOES reported a long duration C3.6 
			X-ray flare on NOAA AR 10904 (S16W08) between 14:37 -
 			19:22 UT with peak emission at 16:17 UT. EIT 195 
			images show a brightening on AR 10904 starting at 
			16:24 UT, peaking at around 17:12 UT. Nice post-flare
 			loops. Formation of a dimming region all around the 
			AR, most discernible to S of AR.

2006/08/17 (Thursday)

	NO LASCO C2/C3 CME watch during 2006/08/17 and 08/18 
	due to a special Observation campaign with EIT 
	(7 minute high cadence run in 304A until 08/18 22:00 UT, 
	afterward CCD EIT Bakeout).