NOAA AR 2157 (Catania number 45) produced numerous C-class flares during the past 24 hours, the strongest of them being the C8.0 flare peaking today at 08:14 UT. This active region has beta-gamma-delta configuration of its photospheric magnetic field, so we expect more flaring activity up to the M-level, mostly from this sunspot group. An isolated X-class flare is possible but unlikely. The C8.0 flare was accompanied by coronal dimmings indicating the eruption of a CME. However, there is no SOHO/LASCO data yet to confirm the CME occurrence. A partial halo CME was detected yesterday first appearing in the LASCO C2 field of view at 19:24 UT. STEREO B EUVI data show that its source region was located on the far side of the Sun (filament eruption around N15E160 as seen from the Earth), so this CME will not have geomagnetic consequences. The solar proton flux is just below the SEP event threshold, so we maintain the warning condition for a proton event. Since around 04:00 UT today, the interplanetary magnetic field (IMF) magnitude is elevated (up to 12 nT) indicating the arrival of an ICME, probably corresponding to the partial halo CME detected on the Sun on September 2. Due to low solar wind speed (around 350 km/s), the geomagnetic conditions remained quiet to unsettled. The IMF now turned northward, so the geomagnetic conditions are quiet and are expected to remain so.
Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Time UT: 16:00
Exposure 1/500 sec.