The strongest solar flare reported during the past 24 hours was a C4.0 flare (peaked at 23:29 UTC, on December 17). The flare seems to originate from Catania sunspot region 91 (no NOAA number yet) located on the east solar limb. New Catania sunspot group 87 (NOAA AR 1928) shows some activity
at the same moment. NOAA AR 1928 is growing and currently also has the beta-gamma magnetic configuration of its photospheric field (just like sunspot region 80 or NOAA AR 1917). The probability for C-flares is around 80%, M-flares around 30%, with Catania sunspot regions 80, 87 and 91 as main source candidates. The chances for an X-flare are low. No Earth-directed CMEs were observed.Solar wind conditions are stable with a solar wind speed of 400 km/s and a magnitude of the interplanetary magnetic field of 5 nT (observed by ACE). Geomagnetic conditions are quiet (K<3). A glancing blow of the CME of December 16 might lead to unsettled or at most active conditions at the end of December 19 (UTC time).
Equipment: Coronado 90 + SBIG 8300s + LX75
Time UT: 20:00
Exposure 0.8 sec.
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