Solar flares on September 21, 2011
The most powerful solar flare in 24 hours
M1.8 (strong) flare - September 21 at 1:23 PM
Solar activity index
Value as of the end of the day on September 21, 2011
Solar X-ray emission over the past 2 days
Chart of solar X-ray emission (1-8 Å) from September 20, 2011 to September 21, 2011
Time zone — UTC+01 (London) — summer time
List of solar flares for September 21, 2011
The total number of solar flares of class C and higher — 10 flares
C class — 9 | M class — 1 | X class — 0
| Class | begin | max | end | region |
|---|---|---|---|---|
| C2.0 | 21:31 | 21:36 | 21:40 | 1295 |
| C2.1 | 17:47 | 17:49 | 17:51 | — |
| C2.3 | 17:13 | 17:16 | 17:20 | — |
| C2.8 | 16:21 | 16:26 | 16:30 | 1295 |
| C2.7 | 15:37 | 15:38 | 15:41 | 1295 |
| C2.6 | 15:21 | 15:23 | 15:26 | 1295 |
| M1.8 | 13:04 | 13:23 | 13:45 | 1302 |
| C3.9 | 12:17 | 12:24 | 12:28 | 1301 |
| C1.9 | 08:37 | 08:41 | 08:47 | 1295 |
| C2.7 | 01:55 | 02:07 | 02:14 | 1301 |