Daily Sunspot Evaluation
Observation Sheet Friday, 17 December 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)
- 10
- Number of spots (f)
- 60
- Relative number (R)
- 160
- Observer
- FA
- Reading
- all checks consistent
- File
- 19711217.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | D – 17 | 12 | 03E | 181 | |||
| 2 | D – 10 | 10 | 45E | 139 | |||
| 3 | J – 1 | -4 | 51E | 133 | |||
| 4 | A – 1 | -5 | 80E | 104 | |||
| 5 | E – 11 | -14 | 75E | 109 | |||
| 6 | C – 7 | -15 | 03W | 187 | |||
| 7 | B – 2 | -14 | 28W | 212 | |||
| 8 | J – 1 | -3 | 70W | 254 | |||
| 9 | J – 2 | 9 | 56W | 240 | |||
| 10 | G – 8 | 19 | 10W | 194 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.