Daily Sunspot Evaluation
Observation Sheet Monday, 20 September 1971
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)
- 4
- Number of spots (f)
- 29
- Relative number (R)
- 69
- Observer
- FA
- Reading
- all checks consistent
- File
- 19710920.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | A – 1 | -2 | 23E | 243 | |||
| 2 | E – 22 | -12 | 13W | 279 | |||
| 3 | J – 2 | 5 | 15W | 281 | |||
| 4 | J – 4 | 12 | 27W | 293 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.