Daily Sunspot Evaluation
Observation Sheet Thursday, 20 May 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)
- 5
- Number of spots (f)
- 15
- Relative number (R)
- 65
- Observer
- HA
- Reading
- all checks consistent
- File
- 19710520.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | J – 2 | 16 | 35E | 58 | |||
| 2 | J – 1 | 15 | 54E | 39 | |||
| 3 | A – 3 | 13 | 62E | 31 | |||
| 4 | A – 1 | 7 | 63E | 30 | |||
| 5 | J – 8 | 4 | 40W | 133 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.