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Sunspots and active regions
The following active regions with sunspot groups were visible on the Sun on September 21, 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) | |
|---|---|---|---|---|---|---|---|---|
| № 8706 | N20 | E66 | 02 | 0120 | BETA | Sep 27, 1999 | Oct 4, 1999 | Oct 18, 1999 |
| № 8704 | S22 | E28 | 06 | 0110 | BETA | Sep 24, 1999 | Oct 1, 1999 | Oct 15, 1999 |
| № 8700 | N12 | W19 | 18 | 0050 | BETA | Sep 21, 1999 | Sep 27, 1999 | Oct 11, 1999 |
| № 8699 | N24 | W88 | 01 | 0060 | ALPHA | Sep 15, 1999 | Sep 22, 1999 | Oct 6, 1999 |
| № 8695 | N21 | W56 | 01 | 0010 | ALPHA | Sep 18, 1999 | Sep 25, 1999 | Oct 8, 1999 |
Solar cycle progression
The average monthly sunspot number (SSN) from January 1970 to September 1999. The gray background is the average SSN index.
