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Sunspots and active regions
The following active regions with sunspot groups were visible on the Sun on December 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) | |
|---|---|---|---|---|---|---|---|---|
| № 8808 | S18 | W08 | 02 | 0000 | ALPHA | Dec 21, 1999 | Dec 28, 1999 | Jan 11, 2000 |
| № 8807 | N10 | E44 | 06 | 0040 | BETA | Dec 25, 1999 | Jan 1, 2000 | Jan 15, 2000 |
| № 8806 | N19 | E37 | 28 | 1040 | BETA-GAMMA-DELTA | Dec 25, 1999 | Jan 1, 2000 | Jan 14, 2000 |
| № 8804 | S20 | E29 | 02 | 0290 | BETA | Dec 24, 1999 | Dec 31, 1999 | Jan 14, 2000 |
| № 8803 | S13 | W31 | 08 | 0030 | BETA | Dec 20, 1999 | Dec 26, 1999 | Jan 9, 2000 |
| № 8798 | S14 | W21 | 43 | 0460 | BETA-DELTA | Dec 20, 1999 | Dec 27, 1999 | Jan 10, 2000 |
Solar cycle progression
The average monthly sunspot number (SSN) from January 1970 to December 1999. The gray background is the average SSN index.
