Daily Sunspot Evaluation
Observation Sheet Thursday, 15 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)
- 11
- Number of spots (f)
- 71
- Relative number (R)
- 181
- Observer
- SM
- Reading
- all checks consistent
- File
- 19710415.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | G – 3 | 3 | 16E | 179 | |||
| 2 | J – 2 | 20 | 37E | 158 | |||
| 3 | J – 6 | 22 | 49E | 146 | |||
| 4 | G – 9 | 3 | 40E | 155 | |||
| 5 | H – 5 | -6 | 21E | 174 | |||
| 6 | J – 3 | -17 | 45E | 150 | |||
| 7 | A – 1 | -21 | 51E | 144 | |||
| 8 | J – 3 | -15 | 08E | 187 | |||
| 9 | D – 17 | -5 | 11W | 206 | |||
| 10 | C – 21 | -4 | 20W | 215 | |||
| 11 | J – 1 | 15 | 76W | 271 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.