Daily Sunspot Evaluation
Observation Sheet Wednesday, 18 September 1957
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)
- 14
- Number of spots (f)
- 163
- Relative number (R)
- 303
- Observer
- FY
- Reading
- all checks consistent
- File
- 19570918.jpg
Sunspot groups
| No | Group (class – spots) | r | p | Margin no. |
|---|---|---|---|---|
| 1 | F – 66 | 22 | 11 | |
| 2 | A – 1 | 15 | 35 | |
| 3 | E – 31 | 10 | 26 | |
| 4 | C – 9 | -21 | 24 | |
| 5 | A – 1 | -22 | 7 | |
| 6 | A – 1 | -46 | 29 | |
| 7 | J – 1 | -42 | 53 | |
| 8 | B – 6 | -23 | 42 | |
| 9 | B – 8 | -16 | 38 | |
| 10 | A – 2 | -20 | 54 | |
| 11 | A – 5 | -7 | 25 | |
| 12 | D – 7 | 25 | 50 | |
| 13 | C – 9 | 15 | 13 | |
| 14 | D – 16 | 12 | 6 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.