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Sunspots and active regions
The following active regions with sunspot groups were visible on the Sun on October 17, 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) | |
|---|---|---|---|---|---|---|---|---|
| № 8735 | N18 | E40 | 09 | 0010 | BETA | Oct 21, 1999 | Oct 28, 1999 | Nov 11, 1999 |
| № 8734 | N17 | E08 | 01 | 0000 | ALPHA | Oct 19, 1999 | Oct 25, 1999 | Nov 8, 1999 |
| № 8732 | N20 | W12 | 19 | 0210 | BETA | Oct 17, 1999 | Oct 24, 1999 | Nov 7, 1999 |
| № 8731 | N12 | W03 | 62 | 1000 | BETA-GAMMA-DELTA | Oct 18, 1999 | Oct 25, 1999 | Nov 7, 1999 |
| № 8729 | N13 | W25 | 09 | 0020 | BETA | Oct 16, 1999 | Oct 23, 1999 | Nov 6, 1999 |
| № 8728 | N23 | W26 | 29 | 0290 | BETA | Oct 16, 1999 | Oct 23, 1999 | Nov 6, 1999 |
Solar cycle progression
The average monthly sunspot number (SSN) from January 1970 to October 1999. The gray background is the average SSN index.
