The Sun Online and solar activity. September 13, 2014

There are currently 6 sunspot groups visible on the solar disk. The most prominent groups, NOAA 2157 and 2158, are decaying. These groups still have spots of opposite magnetic polarity close to each other. A total of 7 C-class flares were recorded. The strongest flare of the period was a C3.3 peaking at 20:12UT. It occurred in an unnumbered sunspot region close to the southwest limb. NOAA 2166 is a small group embedded in a large plage area in the northeast quadrant, and produced only a C1 flare. Two filament eruptions were observed around 23:50UT and 03:40UT, but the associated CMEs were not Earth directed. Other CMEs, first observed by SOHO/LASCO on 12 September at 18:24UT and 21:48UT, were related to backside events and will not affect Earth. The proton event related to the X1 flare ended at 23:10UT.
Further C-class flaring is expected, with a chance on an M-class flare. The arrival of the halo CME related to the X1 flare from 10 September was observed by SOHO/CELIAS as a shock in the solar wind on 12 September at 15:27UT. Wind speed increased abruptly from 430 to 670 km/s, and further
increased to a maximum of nearly 800 km/s around 22:00UT. Bz was oriented southward between 20:30 and 22:00UT with maximum values near -17nT, then abruptly turned northward to steady values around +20 nT. The period between 21:00UT and 24:00UT was geomagnetically the most intense, with Kp
reaching 7 (strong geomagnetic storm), and local K-indices at Dourbes and Potzdam reaching 6 (moderate storming). Geomagnetic conditions then quieted down, with currently unsettled to active conditions observed. Quiet to unsettled geomagnetic conditions are expected, with locally a brief active period possible in the aftermath of yesterday’s geomagnetic storm.

Equipment: Coronado 90 +  Imaging Source DMK  + LX75
Processing: Photoshop, Avistack 300 frames
Date: 13/08/14
Time UT: 16:00
Exposure 1/500 sec.

Observatory Sponli