Daily Sunspot Evaluation
Observation Sheet Tuesday, 18 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)
- 6
- Number of spots (f)
- 73
- Relative number (R)
- 133
- Observer
- ET
- Reading
- all checks consistent
- File
- 19510918.jpg
Sunspot groups
| No | Group (class – spots) | r | p | Margin no. |
|---|---|---|---|---|
| 1 | D – 34 | 0.44 | 100 | |
| 2 | B – 13 | 0.84 | 101 | |
| 3 | A – 2 | 0.68 | 256 | |
| 4 | C – 8 | 0.79 | 295 | |
| 5 | C – 15 | 0.64 | 298 | |
| 6 | A – 1 | 0.06 | 322 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.