Daily Sunspot Evaluation
Observation Sheet Saturday, 18 April 1981
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)
- 13
- Number of spots (f)
- 146
- Relative number (R)
- 276
- Observer
- OG
- Reading
- all checks consistent
- File
- 19810418.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | DRC – 26 | 14 | 52W | 232 | 54W | ||
| 2 | CRE – 12 | 11 | 41W | 221 | 43W | ||
| 3 | DAO – 4 | 18 | 38W | 218 | 40W | ||
| 4 | DAO – 4 | 15 | 28W | 208 | 30W | ||
| 5 | CRI – 15 | 25 | 25W | 205 | 27W | ||
| 6 | DSO – 3 | 24 | 02E | 178 | 00 | ||
| 7 | CAI – 17 | 18 | 07E | 173 | 05E | ||
| 8 | CRO – 4 | 12 | 17E | 163 | 15E | ||
| 9 | DAC – 20 | 12 | 28E | 152 | 26E | ||
| 10 | DRC – 11 | 25 | 34E | 146 | 32E | ||
| 11 | HAX – 1 | -4 | 46W | 226 | 48W | ||
| 12 | EKC – 24 | -6 | 13W | 193 | 15W | ||
| 13 | HKX – 5 | -10 | 33E | 147 | 31E |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.