Solar activity was dominated by two C6 flares from NOAA AR 2146 and 2149. The first one, a C6.4 flare from NOAA AR 2149 peaked at 12:57 UT. The second one, a C6.2 flare from NOAA AR 2146 peaked at 15:52 UT. Flaring at C level is expected to continue with a fair chance for an M flare. Yesterdays C2.2 flare peaking at 10:27UT from NOAA AR 2146 was associated with type II radio bursts and with a CME visible in SOHO/LASCO C2 from 11:24 UT onwards. Despite the location of the source region near the
central meridian, the bulk of the mass was expelled in western direction from the sun earth line. The angular width was however underestimated by CACTUS, which due to the weaker additional north-eastern and south-eastern components is almost full halo. The projected speed is around 400 km/s. It was followed by a second partial halo CME first visible in SOHO/LASCO C2 images at 16:36 UT associated to the C6.2 flare peaking at 15:52 from the same region (NOAA AR 2146) and associated type II radio emission. The appearance of the second CME is roughly comparable with the first CME. A
dominant westward component with an additional north-eastern component, but now lacking the south-eastern component. A glancing blow from the combination of both CME’s may be expected around
UT midnight August 26/27.Solar wind conditions were nominal with speeds around 350 km/s (with a maximum of just over 380 km/s around 15:00 UT, and a minimum of just under 310 km/s around 8:30 UT). The total magnetic field is around 4.5 nT with a peak period of around 6 nT and a minimum of around
2 nT. Bz was variable within the +-4nT range. The phi angle was steadily in a positive (away) sector.
Geomagnetic conditions were quiet (both local K Dourbes and NOAA Kp in the 0-2 range). Over the next three days nominal solar wind conditions and quiet geomagnetic conditions are expected. Afterwards, near UT midnight 26/27 we may expect the impact of the August 22 CME’s.
Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Time UT: 16:00
Exposure 1/500 sec.