Daily Sunspot Evaluation
Observation Sheet Saturday, 20 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)
- 16
- Number of spots (f)
- 124
- Relative number (R)
- 284
- Observer
- TA
- Reading
- all checks consistent
- File
- 19910420.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | DKC – 46 | 8 | 52W | 244 | 55W | 9.5 | 169 |
| 2 | AX – 1 | 11 | 43W | 235 | 46W | 179 | |
| 3 | BRI – 5 | 15 | 31W | 223 | 34W | 4 | 180 |
| 4 | DAI – 15 | 13 | 22W | 214 | 25W | 5.5 | 169 |
| 5 | HA – 1 | -26 | 73W | 265 | 76W | 2 | 170 |
| 6 | BXI – 3 | -20 | 50W | 242 | 53W | 6 | 165 |
| 7 | AX – 3 | -13 | 28W | 220 | 31W | 2 | 184 |
| 8 | BXO – 3 | -27 | 28W | 220 | 31W | 5 | 181 |
| 9 | AX – 2 | -10 | 18W | 210 | 21W | 2.5 | 173 |
| 10 | AX – 4 | -14 | 09W | 201 | 12W | 2 | 185 |
| 11 | DAO – 19 | -10 | 00 | 192 | 03W | 8 | 174 |
| 12 | BXI – 7 | -8 | 09E | 183 | 06E | 7 | 178 |
| 13 | HA – 5 | -17 | 10E | 182 | 07E | 1 | 176 |
| 14 | AX – 2 | -28 | 10E | 182 | 07E | 0.5 | 186 |
| 15 | AX – 5 | -24 | 20E | 172 | 17E | 1 | 187 |
| 16 | AX – 3 | -27 | 20E | 172 | 17E | 1 | 188 |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.