LASCO Activity Report for
December 16, 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

- Telemetry Keyhole # 7: 2004/12/13 - 2004/12/29

- EIT pre-bake cals taken on Saturday 2004/12/11 between 15:24-18:30 UT. The 
  CCD bakeout started at 18:47 UT. The end of the bakeout will be on 2004/12/28
  at 10:00 UT. Therefore, no EIT images during that period.

- During the Keyhole, LASCO will observe with DSN gap recording availability
  thanks to the FOT and the SOCs hard work. C2 and C3 will observe at a 
  standard synoptic plan of C2 at 10 minute cadence and C3 at the 30 minute
  cadence with the daily pB and flat field images.

SOHO Telemetry Submode is in Submode 5.

2004/12/15 (Wednesday)

	  S West	Small and faint blob-like fronts along streamer since 
			early on previous day, all along the day.

06:12 UT  W Limb	Faint, elongated, and thin loop-like structure 
			preceeding at ~ 08:24 UT another elongated and ragged
			structure. Please note that prior to the event, by ~
			04:36 UT, a jet-like front develops slightly toward WNW.

	10:00 - 16:36 UT 	Temporary Data Gap. 

17:36 UT  N - N West	The event was first seen in C2 at 17:36 UT above the 
	    (HALO)	NW limb as well as on the N Pole. Extremely faint 
			extensions above the S Pole and SW Limb can also be 
			seen, giving to the event the appearance of a Full 
			Halo. The development of the event shows a ragged
			loop-like structure moving out toward NW (1), a little
			behind a much wider (and fainter) ragged structure (2)
			that extends all above the W Limb, N Pole, and up to 
			the SE Limb. The whole event was first seen in C3 at
			18:42 UT all above the N Pole. Extensions to S are 
			barely discernible. The mean plane-of-sky speed (based 
			on C3 data) of the structure moving toward NW (1)
			measured at PA 311 was about 483 km/sec, showing
			practically no acceleration. As for the wide ragged
			structure (2), the speed at a couple of PA was (the
			corresponding HT profiles also show practically no
			acceleration): PA 315: 524 km/sec; PA 000: 516 km/sec.
			No significant X-ray activity was reported by GOES by 
			the time. There were no EIT images as EIT is performing 
			a CCD bakeout (2004/12/11 - 2004/12/28. In summary, 
			and taking into account the very faint extensions to S,
			the event has therefore been determined as a 'full' 
			halo event, most probably backsided.

18:48 UT  WN West	In the aftermath of (1) -see previous event- a faint
			and ragged loop structure can be discerned. Very faint
			extensions to N. By 23:24 UT (after following data gap)
			structured material.

	21:48 - 23:12 UT 	Temporary Data Gap. 

20:48 UT  EN East	Pair formation (couple of small blobs coming out and 
			in, respectively). Separation point: ~4.35 solar radii
			at PA ~ 77.

23:24 UT  W Limb	Elongated and expanding loop-like structure developing
			slightly toward WSW.

2004/12/16 (Thursday)

04:24 UT  S East	Elongated spray-like front.

Last image analyzed taken at 10:24 UT (C2 time).