Daily Sunspot Evaluation
Observation Sheet Friday, 20 April 1951
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)
- 6
- Number of spots (f)
- 83
- Relative number (R)
- 143
- Observer
- ET
- Reading
- all checks consistent
- File
- 19510420.jpg
Sunspot groups
| No | Group (class – spots) | r | p | Margin no. |
|---|---|---|---|---|
| 1 | A – 2 | 0.82 | 73 | |
| 2 | C – 4 | 0.85 | 79 | |
| 3 | A – 2 | 0.46 | 233 | |
| 4 | J – 4 | 0.72 | 243 | |
| 5 | F – 70 | 0.46 | 282 | |
| 6 | A – 1 | 0.56 | 290 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.