Daily Sunspot Evaluation
Observation Sheet Tuesday, 21 July 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)
- 4
- Number of spots (f)
- 33
- Relative number (R)
- 73
- Observer
- FL
- Reading
- all checks consistent
- File
- 19870721.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | CRI – 12 | 21 | 08E | 251 | 05E | 3.5 | 43 |
| 2 | DAO – 5 | -23 | 75E | 184 | 72E | 10.5 | 44 |
| 3 | CRI – 12 | -29 | 04E | 255 | 01E | 8.5 | 42 |
| 4 | HKX – 4 | -31 | 17E | 242 | 14E | 3.4 | 41 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.