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Sunspots and active regions
The following active regions with sunspot groups were visible on the Sun on September 23, 1999. Coordinates are given as of the end of the day.
| Group ID | Location | Number of sunspots | Area (msh) | Type | CM Passage | Disappearance (W90) | Reappearance (W270) | |
|---|---|---|---|---|---|---|---|---|
| № 8708 | S09 | E53 | 09 | 0040 | BETA | Sep 28, 1999 | Oct 5, 1999 | Oct 19, 1999 |
| № 8707 | S07 | W10 | 03 | 0000 | BETA | Sep 23, 1999 | Sep 30, 1999 | Oct 14, 1999 |
| № 8706 | N19 | E36 | 02 | 0090 | ALPHA | Sep 27, 1999 | Oct 4, 1999 | Oct 18, 1999 |
| № 8704 | S22 | W01 | 14 | 0120 | BETA | Sep 24, 1999 | Oct 1, 1999 | Oct 15, 1999 |
| № 8702 | N23 | W55 | 02 | 0000 | BETA | Sep 20, 1999 | Sep 27, 1999 | Oct 11, 1999 |
| № 8700 | N13 | W49 | 13 | 0040 | BETA | Sep 20, 1999 | Sep 27, 1999 | Oct 11, 1999 |
Solar cycle progression
The average monthly sunspot number (SSN) from January 1970 to September 1999. The gray background is the average SSN index.
