Daily Sunspot Evaluation
Observation Sheet Thursday, 17 September 1970
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)
- 36
- Relative number (R)
- 146
- Observer
- HA
- Reading
- counts consistent, some coordinates doubtful
- File
- 19700917.jpg
Sunspot groups
| No | Group (class – spots) | B | Δ L | L | Δ Lf | U | Margin no. |
|---|---|---|---|---|---|---|---|
| 1 | D – 6 | 20 | 66E | 18 | |||
| 2 | C – 4 | 4 | 53E | 31 | |||
| 3 | A – 1 | 6 | 05E | 79 | |||
| 4 | D – 4 | -17 | 47E | 37 | |||
| 5 | C – 8 | -23 | 01W | 85 | |||
| 6 | A – 2 | -9 | 09W | 93 | |||
| 7 | J – 1 | -12 | 36W | 120 | |||
| 8 | A – 1 | -16 | 71W | 155 | |||
| 9 | J – 1 | 8 | 15W | 99 | |||
| 10 | C – 7 | 12 | 20W | 104 | |||
| 11 | J – 1 | 11 | 26W | 140 ⚠ |
Class as written on the sheet (? = group the observer marked as uncertain). ⚠: the coordinates of this row do not agree with each other.