How the telescope remade the universe

Within half a century of its invention in 1608, the telescope had transformed our view of the cosmos and Earth’s place in it.

The telescope’s 400-year revolution

Early telescopes were about 1 inch wide; today’s span some 33 feet. Here’s how this crucial tool moved forward.

Web extra: The early reflectors

Compare the optics of the first three telescope designs.

Scoping out the great discoveries

From Jupiter’s moons to dark energy, scientists have used the telescope to make many extraordinary discoveries.

Experience Galileo’s Italy

Walk in Galileo’s footsteps in Rome, Florence, and other haunts of the great astronomer.

Web extra: William Sheehan’s Galileo

The author of Experience Galileo’s Italy explains his appreciations for the great astronomer’s life and work.

Explore the Great Bear’s galaxies

Break out your medium-size telescope and search Ursa Major’s extragalactic treasures.

Web extra: Observing Ursa Major galaxies through a large scope

Follow along for a night of galaxy hunting from Animas, New Mexico.

25 top telescopes for starry nights

Set up one of these high-quality instruments, and you’ll be in observing heaven.


This Month in Astronomy
Beautiful Universe
Bob Berman’s Strange Universe
Stephen James O’Meara’s Secret Sky
Astro News
The Sky this Month
Glenn Chaple’s Observing Basics
Phil Harrington’s Binocular Universe

Survey the southern sky

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