Daily Sunspot Evaluation
Observation Sheet Wednesday, 17 April 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)
- 12
- Number of spots (f)
- 177
- Relative number (R)
- 297
- Observer
- MB
- Reading
- all checks consistent
- File
- 19910417.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | DKI – 16 | 28 | 52W | 283 | 53W | 5.5 | 155 |
| 2 | EKC – 58 | 8 | 10W | 241 | 11W | 13.5 | 153 |
| 3 | CAI – 17 | 15 | 18E | 213 | 17E | 6 | 169 |
| 4 | CKO – 9 | -26 | 29W | 260 | 30W | 11.5 | 170 |
| 5 | BRO – 13 | -20 | 12W | 243 | 13W | 8 | 165 |
| 6 | AX – 3 | -27 | 01E | 230 | 00 | 0.5 | 166 |
| 7 | BXO – 5 | -11 | 10E | 221 | 09E | 3 | 171 |
| 8 | BXI – 4 | -22 | 28E | 203 | 27E | 4.5 | 172 |
| 9 | BXI – 8 | -10 | 28E | 203 | 27E | 4 | 173 |
| 10 | EKI – 25 | -10 | 41E | 190 | 40E | 12 | 174 |
| 11 | BRO – 13 | -7 | 46E | 185 | 45E | 13.5 | 175 |
| 12 | AX – 6 | -21 | 50E | 181 | 49E | 2.5 | 176 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.