Sunspots and active regions
The following active regions with sunspot groups were visible on the Sun on April 18, 2001. 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) | |
|---|---|---|---|---|---|---|---|---|
| № 9431 | S10 | E46 | 02 | 0010 | Alpha | Apr 23, 2001 | Apr 29, 2001 | May 13, 2001 |
| № 9430 | S17 | W49 | 06 | 0030 | Beta | Apr 16, 2001 | Apr 22, 2001 | May 6, 2001 |
| № 9429 | N08 | E20 | 01 | 0080 | Alpha | Apr 21, 2001 | Apr 28, 2001 | May 11, 2001 |
| № 9426 | S08 | W43 | 04 | 0010 | Beta | Apr 16, 2001 | Apr 23, 2001 | May 6, 2001 |
| № 9424 | S15 | W88 | 02 | 0020 | Beta | Apr 13, 2001 | Apr 19, 2001 | May 3, 2001 |
| № 9422 | S13 | W57 | 03 | 0010 | Beta | Apr 15, 2001 | Apr 22, 2001 | May 5, 2001 |
| № 9420 | S07 | W86 | 01 | 0000 | Alpha | Apr 13, 2001 | Apr 20, 2001 | May 3, 2001 |
Solar cycle progression
The average monthly sunspot number (SSN) from January 1972 to April 2001. The gray background is the average SSN index.
