Daily Sunspot Evaluation
Observation Sheet Saturday, 18 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)
- 11
- Number of spots (f)
- 70
- Relative number (R)
- 180
- Observer
- HM
- Reading
- all checks consistent
- File
- 19711218.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | D – 9 | 10 | 31E | 139 | |||
| 2 | J – 1 | -4 | 37E | 133 | |||
| 3 | A – 2 | -5 | 66E | 104 | |||
| 4 | ? – 3 | -16 | 76E | 94 | |||
| 5 | E – 19 | -14 | 60E | 110 | |||
| 6 | A – 2 | -9 | 03W | 173 | |||
| 7 | J – 2 | -13 | 18W | 188 | |||
| 8 | ? – 1 | -3 | 85W | 255 | |||
| 9 | J – 2 | 9 | 71W | 241 | |||
| 10 | G – 8 | 18 | 24W | 194 | |||
| 11 | G – 21 | 13 | 11W | 181 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.