Drawings he made of a sunspot group in 1607, a new study reveals, show the "tail-end of the solar cycle" with instrumentation before the telescope was more widely available in the early 17th century.

The first telescopes, known as refracting telescopes, were built in the early 17th century by Dutch eyeglass makers.They employed a pair of lenses—one convex fitted at the end of the scope, and ...

When Italian astronomer Galileo Galilei heard rumors of the first practical telescope at the beginning of the 17th century, he was quick to craft his own version and turn it toward the heavens.

Drawings he made of a sunspot group in 1607, a new study reveals, show the "tail-end of the solar cycle" with instrumentation before the telescope was more widely available in the early 17th century.

Drawings he made of a sunspot group in 1607, a new study reveals, show the "tail-end of the solar cycle" with instrumentation before the telescope was more widely available in the early 17th century.

Earth was cooler than usual in the 16th and 17th centuries and scientists are still trying to figure out why. New analysis of sunspot drawings by Kepler, in 1607, may shed some light.

"Half-forgotten" sunspot drawings by Renaissance astronomer Johannes Kepler are showing us more about how the sun's cycle of activities work. "The group's findings … offer a key to resolving the ...