Daily Sunspot Evaluation
Observation Sheet Saturday, 20 April 1957
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)
- 61
- Relative number (R)
- 171
- Observer
- WG
- Reading
- all checks consistent
- File
- 19570420.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | E – 23 | 29 | 31E | ||||
| 2 | H – 7 | -11 | 23E | ||||
| 3 | J – 2 | -15 | 27E | ||||
| 4 | A – 2 | -17 | 37E | ||||
| 5 | G – 2 | -14 | 49E | ||||
| 6 | A – 1 | -16 | 68E | ||||
| 7 | J – 1 | -26 | 72E | ||||
| 8 | D – 10 | -13 | 12E | ||||
| 9 | C – 2 | -18 | 5W | ||||
| 10 | A – 1 | -13 | 19W | ||||
| 11 | B – 10 | 25 | 23W |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.