Daily Sunspot Evaluation
Observation Sheet Thursday, 28 February 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)
- 11
- Number of spots (f)
- 83
- Relative number (R)
- 193
- Observer
- YK
- Reading
- all checks consistent
- File
- 19910228.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | AX – 1 | 16 | 49W | 194 | 52W | 0.5 | 99 |
| 2 | CAO – 7 | 17 | 30W | 175 | 33W | 6 | 91 |
| 3 | BXI – 9 | 28 | 30W | 175 | 33W | 9 | 94 |
| 4 | CAI – 13 | 3 | 21E | 124 | 18E | 5.5 | 95 |
| 5 | ? – 1 | -16 | 86W | 231 | 89W | - | 79 |
| 6 | EKC – 9 | -22 | 50W | 195 | 53W | 15 | 84 |
| 7 | DKC – 24 | -15 | 44W | 189 | 47W | 9 | 85 |
| 8 | BXO – 3 | -12 | 33W | 178 | 36W | 3 | 96 |
| 9 | CAI – 8 | -7 | 13W | 158 | 16W | 8.5 | 97 |
| 10 | AX – 2 | -17 | 08W | 153 | 11W | 1.5 | 100 |
| 11 | CAO – 6 | -11 | 06W | 151 | 09W | 2.5 | 98 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.