Daily Sunspot Evaluation
Observation Sheet Tuesday, 17 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)
- 67
- Relative number (R)
- 157
- Observer
- HE
- Reading
- all checks consistent
- File
- 19910917.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | AX – 2 | 9 | 06E | 1 | 05E | 2 | 515 |
| 2 | HS – 7 | 1 | 08E | 359 | 07E | 3.5 | 502 |
| 3 | AX – 1 | 13 | 11E | 356 | 10E | - | 517 |
| 4 | CAI – 26 | 7 | 24E | 343 | 23E | 9.5 | 505 |
| 5 | BKI – 5 | -21 | 42W | 49 | 43W | 5.5 | 499 |
| 6 | CAO – 15 | -22 | 25W | 32 | 26W | 6.5 | 500 |
| 7 | HS – 3 | -11 | 07W | 14 | 08W | 2.5 | 501 |
| 8 | BXI – 7 | -12 | 06E | 1 | 05E | 3 | 518 |
| 9 | AX – 1 | -21 | 35E | 332 | 34E | - | 519 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.