Daily Sunspot Evaluation
Observation Sheet Thursday, 13 September 1951
There is no typed record for this day. The values below were read by computer from the table on the sheet; when in doubt, see the drawing. Details →
- Number of groups (g)
- 11
- Number of spots (f)
- 68
- Relative number (R)
- 178
- Observer
- WG
- Reading
- all checks consistent
- File
- 19510913.jpg
Sunspot groups
| No | Group (class – spots) | r | p | Margin no. |
|---|---|---|---|---|
| 1 | J – 3 | 0.22 | 64 | |
| 2 | A – 1 | 0.93 | 105 | |
| 3 | A – 1 | 0.89 | 108 | |
| 4 | E – 19 | 0.42 | 111 | |
| 5 | D – 19 | 0.22 | 121 | |
| 6 | C – 13 | 0.68 | 140 | |
| 7 | A – 1 | 0.78 | 141 | |
| 8 | A – 1 | 0.89 | 141 | |
| 9 | C – 6 | 0.66 | 152 | |
| 10 | A – 1 | 0.84 | 276 | |
| 11 | J – 3 | 0.74 | 284 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.