Daily Sunspot Evaluation
Observation Sheet Friday, 21 April 1972
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)
- 7
- Number of spots (f)
- 39
- Relative number (R)
- 109
- Observer
- HM
- Reading
- all checks consistent
- File
- 19720421.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | J – 1 | 18 | 75E | 251 | |||
| 2 | J – 1 | -6 | 76E | 250 | |||
| 3 | H – 21 | -10 | 07E | 319 | |||
| 4 | C – 11 | -11 | 07W | 333 | |||
| 5 | A – 1 | -9 | 44W | 10 | |||
| 6 | J – 1 | 7 | 62W | 28 | |||
| 7 | B – 3 | 14 | 12W | 338 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.