LASCO and EIT observed a full 360 degree halo CME yesterday, 1999/09/20. This was a very faint event in LASCO, visible only in running difference movies. The CME first appeared in C2 at 06:06 UT, and in later frames it was visible as a ring extending all the way around the occulter. The measured plane-of-sky speed in C3 is about 450 km/s at PA 0 (North pole). Because this is a faint event, and the leading edge is rather fuzzy, this is a very approximate speed. EIT observed a filament eruption from the southern portion of the solar disk, close to central meridian, beginning at about 03:48 UT. Following the filament eruption, a bright arcade of loops formed in the same location, beginning at about 06:00 UT. This is the most probable source of the halo CME. Images and movies of the event are available at the LASCO ftp server: ftp://ares.nrl.navy.mil/pub/lasco/halo/19990920. Best wishes, Simon Plunkett. +----------------------------------------------------------------------+ | Simon Plunkett, E-mail: plunkett@kreutz.nascom.nasa.gov | | USRA, Mail Code 682.3, | | NASA Goddard Space Flight Center, Phone: +1-301-286-2941 | | Building 26, Room G-1, +1-301-286-3447 | | Greenbelt, MD 20771. Fax: +1-301-286-0264 | +----------------------------------------------------------------------+