Daily Sunspot Evaluation
Observation Sheet Thursday, 21 October 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)
- 52
- Relative number (R)
- 92
- Observer
- HA
- Reading
- all checks consistent
- File
- 19711021.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | F – 41 | 8 | 08E | 209 | |||
| 2 | B – 2 | 18 | 29E | 188 | |||
| 3 | ? – 1 | -5 | 85E | 132 | |||
| 4 | B – 8 | -12 | 13E | 204 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.