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Sunspots and active regions
The following active regions with sunspot groups were visible on the Sun on April 20, 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) | |
|---|---|---|---|---|---|---|---|---|
| № 8521 | N34 | W06 | 03 | 0000 | BETA | Apr 20, 1999 | Apr 28, 1999 | May 12, 1999 |
| № 8520 | N20 | E13 | 05 | 0020 | BETA | Apr 22, 1999 | Apr 29, 1999 | May 13, 1999 |
| № 8518 | S14 | E41 | 11 | 0100 | BETA | Apr 24, 1999 | May 1, 1999 | May 14, 1999 |
| № 8517 | N22 | W62 | 05 | 0070 | BETA | Apr 16, 1999 | Apr 23, 1999 | May 7, 1999 |
| № 8516 | S18 | E04 | 05 | 0070 | BETA | Apr 21, 1999 | Apr 28, 1999 | May 12, 1999 |
| № 8514 | S31 | W84 | 01 | 0010 | ALPHA | Apr 14, 1999 | Apr 21, 1999 | May 6, 1999 |
Solar cycle progression
The average monthly sunspot number (SSN) from January 1970 to April 1999. The gray background is the average SSN index.
