Daily Sunspot Evaluation
Observation Sheet Tuesday, 13 April 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)
- 51
- Relative number (R)
- 151
- Observer
- FA
- Reading
- all checks consistent
- File
- 19710413.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | J – 1 | 19 | 63E | 158 | |||
| 2 | A – 2 | 20 | 75E | 146 | |||
| 3 | D – 9 | 9 | 68E | 153 | |||
| 4 | E – 7 | 3 | 42E | 179 | |||
| 5 | D – 14 | -5 | 15E | 206 | |||
| 6 | H – 3 | -6 | 47E | 174 | |||
| 7 | ? – 5 | -19 | 73E | 148 | |||
| 8 | A – 4 | -15 | 41W | 262 | |||
| 9 | A – 3 | -4 | 24W | 245 | |||
| 10 | J – 3 | 16 | 50W | 271 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.