Daily Sunspot Evaluation
Observation Sheet Thursday, 17 September 1987
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)
- 2
- Number of spots (f)
- 5
- Relative number (R)
- 25
- Observer
- HM
- Reading
- all checks consistent
- File
- 19870917.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | CAI – 4 | -32 | 16W | 229 | 19W | 4.5 | 67 |
| 2 | ? – 1 | 12 | 82E | 131 | 79E | 2.78 | 68 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.