Daily Sunspot Evaluation
Observation Sheet Sunday, 18 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)
- 9
- Number of spots (f)
- 70
- Relative number (R)
- 160
- Observer
- DK
- Reading
- all checks consistent
- File
- 19710418.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | G – 10 | 10 | 01°E | 155 | |||
| 2 | D – 27 | 20 | 08°E | 148 | |||
| 3 | ? – 2 | -10 | 82°E | 74 | |||
| 4 | B – 6 | -17 | 06°E | 150 | |||
| 5 | H – 10 | -6 | 19°W | 175 | |||
| 6 | J – 1 | -5 | 63°W | 219 | |||
| 7 | J – 1 | -3 | 54°W | 210 | |||
| 8 | G – 6 | 2 | 24°W | 180 | |||
| 9 | C – 7 | 20 | 02°W | 158 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.