Daily Sunspot Evaluation
Observation Sheet Thursday, 20 September 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)
- 4
- Number of spots (f)
- 67
- Relative number (R)
- 107
- Observer
- WG
- Reading
- all checks consistent
- File
- 19510920.jpg
Sunspot groups
| No | Group (class – spots) | r | p | Margin no. |
|---|---|---|---|---|
| 1 | E – 35 | 0.08 | 15 | |
| 2 | D – 18 | 0.54 | 48 | |
| 3 | C – 10 | 0.75 | 110 | |
| 4 | ? – 4 | 0.9 | 299 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.