Kepler Sketched the Sun in 1607. Astronomers Pinpointed the Solar Cycle

Kepler’s 1607 pioneering sunspot sketches solve solar mysteries 400 years later - EurekAlert

Sun blasts out most powerful flare of current solar cycle, sends massive coronal mass ejection into space (video)

Kepler's 1607 pioneering sunspot sketches solve solar mysteries 400 years later