Daily Sunspot Evaluation
Observation Sheet Tuesday, 18 September 1990
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)
- 61
- Relative number (R)
- 151
- Observer
- SG0
- Reading
- all checks consistent
- File
- 19900918.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | HH – 1 | 10 | 17W | 151 | 20W | 3 | 423 |
| 2 | EAI – 14 | 23 | 03W | 137 | 06W | 11 | 430 |
| 3 | CAO – 4 | 19 | 15E | 119 | 12E | 6 | 431 |
| 4 | ? – 2 | -17 | 72W | 206 | 75W | 1 | 433 |
| 5 | HS – 1 | -10 | 41W | 175 | 44W | 1.5 | 419 |
| 6 | CAO – 15 | -13 | 08W | 142 | 11W | 16 | 428E1 |
| 7 | HK – 19 | -13 | 31E | 103 | 28E | 9 | 436E2 |
| 8 | AR – 4 | -8 | 57E | 77 | 54E | 3.5 | 441 |
| 9 | ? – 1 | -24 | 77E | 57 | 74E | 4 | 442 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.