Solar activity increased dramatically this reporting week (April
11-17), and thirteen new sunspot groups emerged. One appeared on
April 11, two more on April 13, three more on April 14, another two
on April 15, one more on April 16 and another two on April 17. On
April 18 an additional two sunspot groups emerged, and the daily
sunspot number increased to 247.
The daily sunspot number was 199 on April...
