LASCO Activity Report for
July 26, 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

2005/07/25 (Monday)

	  EN East	Much gusty ouflow in the form of small ragged fronts
			(aftermath of Partial Halo CME that started on previous
			day at 22:30 UT).

01:31 UT  NN East	Faint elongated and expanding (toward the N Pole) loop
			front. It fades throughout C3.

11:06 UT  E Limb	Ragged front just appearing above the E Limb. By 11:30
			UT, the LE of the ragged front (now seen as a wide and
			ragged loop front) already reached the outer edge of C2.
			Faint extensions reach the W limb by 11:54 UT, the C2
			occulting disk being fully covered by 12:43 UT (the
			signal is again extremely faint above the SW limb). The
			event is first seen in C3 at 11:18 UT, just appearing
			above the E Limb. By 11:42 UT faint extensions cover 
			both the N and S poles. The C3 occulting disk is fully
			covered by 12:18 UT. The mean plane-of-sky speed of 
			the LE at PA 068 was ~ 1590 km/sec. GOES reported
			extremely low X-ray activity during the day (A-class). 
			Likewise, EIT 195 images did not show any significant
			activity on the disk. However, it did show signatures 
			of an important backsided CME all above the E Limb
			starting at around 11:00 UT. In summary, the event has
			therefore been classified as an asymmetric full halo
			event, backsided. 

	15:00 - 17:00 UT	No LASCO C2/C3 CME watch images.
				High Cadence C2 PBs subfield images for the
				Faraday Rotation Study with Cassini Campaign.

17:30 UT  N East	Faint elongated and expanding loop front already under
			development after gap.

21:54 UT  E Limb	Very bright ragged loop front. Faint and diffuse 
			extensions to N and S. By 23:30 UT, faint extensions 
			can be seen past the N Pole up to the W Limb. The
			extensions on the western hemisphere are barely visible
			in C3 and only close to its inner edge. The mean plane-
			of sky speed of the ragged LE at ~ PA 90 was about
			1480 km/sec, showing practically no acceleration. GOES
			reported no significant X-ray activity on the disk 
			during the day. Likewise, EIT 195 images do not show
			significant activity on the disk by the time of the
			event. However, it does show signatures of a backsided
			CME above the E Limb, starting at 21:36 UT.

2005/07/26 (Tuesday)

03:54 UT  EN East	Jet-like front.

04:54 UT  EN East	Very bright and wide ragged loop front. Faint and 
			diffuse extensions to N and S. As it happened with
			previous event, faint extensions can be seen past the 
			N Pole up to the W Limb by 05:30 UT. An extremely
			weak signal can be seen on SW by 06:30 UT. Signatures
			of the event in the western hemisphere are practically
			non-discernible in C3.  The mean plane-of sky speed of
			the ragged LE at ~ PA 85 was ~ 1290 km/sec, showing
			practically no acceleration. Again, EIT 195 images do 
			not show significant activity on the disk by the time 
			of the event. But it does show a backsided CME above
			the ENE limb starting by 04:24 UT. 

09:30 UT  E Limb	Bright loop front just appearing develops as a very
			bright ragged and wide loop front with faint and diffuse
			extensions to N and S. By 09:54 UT, the LE on E is
			already past the outer edge of the C2 FOV. The brightest
			structure develops toward ESE. The event is first seen 
			in C3 at 09:42 UT, just appearing above the E Limb. 
			By 10:19 UT, faint extension surround the main structure,
			on S well past the S Pole. The angular extent of the
			event at 11:42 UT is about 230 deg (from PA 005 - 235),
			extremely faint on SW. Note that the last C3 image where
			the event can be seen is at 14:18 UT (there is afterward
			a gap between 15:00 - 17:00 UT due to the especial PBs
			images for the Faraday Rotation Study still under way).
			The mean plane-of-sky speed of the ragged LE at PA 082
			was ~1800 km/sec (based on only the first 3 C3 frames
			were the event is seen, as the LE becomes then too faint
			and diffuse for accurate measurements). EIT 195 images 
			do not show significant activity on the disk that could
		 	be related to the event by the time of the event.
			However, it does show signatures of an important (and
			still backsided) CME above the E Limb, first clearly 
			seen at 09:24 UT. In summary, the event has therefore
			been classified as at least a Partial Halo event,
			backsided.