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Sunspots and active regions
The following active regions with sunspot groups were visible on the Sun on December 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) | |
|---|---|---|---|---|---|---|---|---|
| № 8804 | S18 | E79 | 01 | 0120 | ALPHA | Dec 24, 1999 | Dec 31, 1999 | Jan 14, 2000 |
| № 8803 | S14 | E25 | 12 | 0040 | BETA | Dec 20, 1999 | Dec 27, 1999 | Jan 9, 2000 |
| № 8802 | S23 | E05 | 04 | 0010 | BETA | Dec 18, 1999 | Dec 25, 1999 | Jan 8, 2000 |
| № 8800 | N09 | E34 | 01 | 0010 | ALPHA | Dec 20, 1999 | Dec 27, 1999 | Jan 10, 2000 |
| № 8798 | S14 | E35 | 26 | 0410 | BETA | Dec 21, 1999 | Dec 27, 1999 | Jan 10, 2000 |
| № 8797 | S32 | W28 | 11 | 0090 | BETA | Dec 16, 1999 | Dec 23, 1999 | Jan 6, 2000 |
| № 8796 | S25 | W44 | 01 | 0000 | ALPHA | Dec 15, 1999 | Dec 21, 1999 | Jan 4, 2000 |
| № 8794 | S14 | W26 | 10 | 0030 | BETA | Dec 16, 1999 | Dec 23, 1999 | Jan 5, 2000 |
Solar cycle progression
The average monthly sunspot number (SSN) from January 1970 to December 1999. The gray background is the average SSN index.
