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Sunspots and active regions
The following active regions with sunspot groups were visible on the Sun on April 16, 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) | |
|---|---|---|---|---|---|---|---|---|
| № 8516 | S19 | E53 | 08 | 0050 | BETA | Apr 21, 1999 | Apr 28, 1999 | May 12, 1999 |
| № 8515 | S18 | W22 | 14 | 0040 | BETA | Apr 15, 1999 | Apr 22, 1999 | May 6, 1999 |
| № 8514 | S33 | W35 | 07 | 0020 | BETA | Apr 14, 1999 | Apr 22, 1999 | May 6, 1999 |
| № 8513 | S17 | W36 | 04 | 0010 | BETA | Apr 14, 1999 | Apr 21, 1999 | May 5, 1999 |
| № 8512 | S27 | W46 | 01 | 0000 | ALPHA | Apr 14, 1999 | Apr 21, 1999 | May 5, 1999 |
| № 8511 | S17 | W63 | 01 | 0000 | ALPHA | Apr 12, 1999 | Apr 19, 1999 | May 3, 1999 |
Solar cycle progression
The average monthly sunspot number (SSN) from January 1970 to April 1999. The gray background is the average SSN index.
