Daily Sunspot Evaluation
Observation Sheet Friday, 21 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)
- 4
- Number of spots (f)
- 15
- Relative number (R)
- 55
- Observer
- HA
- Reading
- all checks consistent
- File
- 19710521.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | J – 3 | 17 | 20E | 60 | |||
| 2 | J – 1 | 15 | 41E | 39 | |||
| 3 | C – 8 | 13 | 48E | 32 | |||
| 4 | J – 3 | 5 | 54W | 134 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.