Solar flares on September 21, 2011
The most powerful solar flare in 24 hours
M1.8 (strong) flare - September 21 at 5:23 AM
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-07 (Carson City) — 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 |
|---|---|---|---|---|
| C6.6 | 21:20 | 21:28 | 21:41 | 1295 |
| C2.0 | 13:31 | 13:36 | 13:40 | 1295 |
| C2.1 | 09:47 | 09:49 | 09:51 | — |
| C2.3 | 09:13 | 09:16 | 09:20 | — |
| C2.8 | 08:21 | 08:26 | 08:30 | 1295 |
| C2.7 | 07:37 | 07:38 | 07:41 | 1295 |
| C2.6 | 07:21 | 07:23 | 07:26 | 1295 |
| M1.8 | 05:04 | 05:23 | 05:45 | 1302 |
| C3.9 | 04:17 | 04:24 | 04:28 | 1301 |
| C1.9 | 00:37 | 00:41 | 00:47 | 1295 |