Daily Sunspot Evaluation
Observation Sheet Sunday, 21 February 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)
- 7
- Number of spots (f)
- 36
- Relative number (R)
- 106
- Observer
- HA
- Reading
- all checks consistent
- File
- 19710221.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | H – 3 | -7 | 47E | 126 | |||
| 2 | J – 1 | -9 | 68E | 105 | |||
| 3 | E – 17 | -17 | 32E | 141 | |||
| 4 | J – 5 | -13 | 16W | 189 | |||
| 5 | J – 1 | -13 | 29W | 202 | |||
| 6 | D – 7 | 20 | 59W | 232 | |||
| 7 | G – 2 | 17 | 45W | 218 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.