(Refraction refers to the passage of light from one medium into another-in this case, from air into a glass lens.) The German astronomer Johannes Kepler presented an approximate mathematical analysis of the focusing properties of lenses in Dioptrice (1611). The Italian astronomer Galileo quickly improved upon the design of the refracting telescope and used it in his discoveries of the moons of Jupiter and the rings of Saturn in 1610.

Compound microscopes were first constructed in the Netherlands between 15 (probably by Hans and Zacharias Jansen), and most sources credit another Dutchman, Hans Lippershey, with the invention of the telescope in 1608. With the dawn of the 17th century, significant progress was reawakened in Europe. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!.Learn about the major environmental problems facing our planet and what can be done about them! Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.Demystified Videos In Demystified, Britannica has all the answers to your burning questions.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.

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