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.
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.
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.
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
Bob Berman’s Strange Universe
Stephen James O’Meara’s Secret Sky
The Sky this Month
Glenn Chaple’s Observing Basics
Phil Harrington’s Binocular Universe
Survey the southern sky