Daily Sunspot Evaluation
Observation Sheet Saturday, 21 September 1991
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)
- 9
- Number of spots (f)
- 75
- Relative number (R)
- 165
- Observer
- YK
- Reading
- all checks consistent
- File
- 19910921.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | BXO – 4 | 7 | 69W | 25 | 72W | 4 | 524 |
| 2 | HS – 1 | 2 | 44W | 0 | 47W | 2 | 502 |
| 3 | CSI – 37 | 8 | 30W | 346 | 33W | 14 | 505 |
| 4 | AX – 3 | 10 | 15E | 301 | 12E | 1.5 | 521 |
| 5 | AX – 7 | 7 | 57E | 259 | 54E | 3 | 527 |
| 6 | HS – 1 | -12 | 59W | 15 | 62W | 2 | 501 |
| 7 | EAI – 10 | -13 | 25W | 341 | 28W | 5 | 526 |
| 8 | BXI – 11 | -12 | 13E | 303 | 10E | 5.5 | 528 |
| 9 | AX – 1 | -11 | 63E | 253 | 60E | - | 529 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.