The world of amateur telescope making has lost a charismatic optical engineer and innovator at age 82. One of the "big guns" of yesteryear, John Gregory introduced the Gregory-Maksutov telescope design, giving basement mirror makers a high-end alternative to, well, just mirrors.

A European comet-chaser has made its third and final flyby of its home planet, taking a few snapshots when it was nearby.

It took more than a month of fevered analysis, but NASA scientists are at last convinced that October 9th's crash by the LCROSS spacecraft on a shadowed lunar plain vaporized at least 100 kg of water.

Did Armstrong and Aldrin really walk the Moon? An incredible new image from NASA's Lunar Reconnaissance Orbiter should erase any naysayer's lingering doubt.

The world won't end on December 21, 2012, no matter what ancient Mayan prophecies might imply. Noted archaeoastronomer E. C. Krupp explains the cause of this mania in November's Sky & Telescope. But this issue is no longer available on newsstands, so we're making Krupp's article available as a free download.

Is there a neutron star lurking at the heart of the spectacular supernova remnant or something much weirder? A new analysis of observations suggests a surprising answer.

An orbiting camera has spotted NASA's Phoenix lander amid deepening dry-ice snow in the Martian arctic. Hardly anyone expects the craft to have survived the long, dark, bitterly cold winter — but engineers will attempt to reestablish contact anyway in a few weeks.

NASA's new planet-hunting spacecraft, launched seven months ago, has a few noisy detectors that make the stars under study appear to flicker. It's a problem the mission team knew about — and decided not to repair before sending the craft irretrievably into space.

When NASA's Messenger spacecraft zipped past the innermost planet for a third and final flyby on September 29th, a glitch caused half of the planned observations to be lost. Scientists are thrilled to have the other half — but they're not entirely sure what to make of them.

NASA scientists haven't said much since a spacecraft and its carrier rocket slammed into a lunar crater on October 9th. One reason might be that they can't believe what they're finding there.

A new analysis showing a cloud of high-energy particles hovering around the center of the Milky Way could be the signature of dark matter and evidence of a “dark force”, but not everyone is convinced.

A gamma-ray burst seen to occur last April happened in the era of the earliest stars, when the universe was only 630 million years old and the "reionization era" was getting under way. But this news isn't exactly news.

As if this island nation hasn't been troubled enough by recent earthquakes, impact specialists confirm that a cosmic "bomb" — likely the most powerful in 15 years — exploded noisily (but harmlessly) over one of its provinces on October 8th.

Surprising advances in radio astronomy have put astronomers within reach of imaging the supermassive black hole in the Milky Way and the active galaxy M87.