Daily Sunspot Evaluation
Observation Sheet Saturday, 17 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)
- 8
- Number of spots (f)
- 90
- Relative number (R)
- 170
- Observer
- MA
- Reading
- all checks consistent
- File
- 19710417.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | J – 3 | 20 | 11°E | 158 | |||
| 2 | G – 16 | 9 | 14°E | 155 | |||
| 3 | E – 22 | 20 | 22°E | 147 | |||
| 4 | J – 7 | -17 | 19°E | 150 | |||
| 5 | H – 15 | -5 | 06°W | 175 | |||
| 6 | C – 12 | -4 | 38°W | 207 | |||
| 7 | D – 8 | -5 | 48°W | 217 | |||
| 8 | G – 7 | 3 | 10°W | 173 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.