SUNSET: 
Hubble Telescope's Silver Anniversary
It's been 25 years since the Space Shuttle Discovery lofted the Hubble Space Telescope into orbit. Yet astronomers were not unanimous in their enthusiasm for the project, as this debate from 1990 recalls.
Celebrate the Night Sky During April
Amateur skygazers can satisfy their celestial cravings with Globe at Night, International Dark-Sky Week, Astronomy Day, and Global Astronomy Month.
Walter H. Haas (1917–2015)
Amateur astronomy has lost a true pioneer, a keen observer who founded the worldwide Association of Lunar and Planetary Observers.
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Saturday's Lunar Eclipse: Not Total?
Most sources say April 4th's lunar eclipse will be total, though only barely so. However, those calculations have overlooked a subtle factor that might render the event only "partial."
Tour April's Sky: Critters on the March
The stars of northern winter linger in the west as celestial bears, a lion, and a snake climb in the east. Meanwhile, Jupiter and Venus sparkle overhead.
Reports from March 20th's Total Solar Eclipse
With risky prospects on far-northern islands and at a premium aboard aircraft, observers looked on with awe as the Moon's shadow swept across the Arctic Ocean
Getting to Totality: Not Easy!
As the countdown for Friday's total solar eclipse nears zero, "umbraphiles" from around the world are flocking to remote parts of the far north in the hope of finding clear skies.
Lots of Lunar Layers Under Chang'e 3
A radar sounder aboard China's first-ever lunar lander found at least nine discrete subsurface layers at its landing site in northern Mare Imbrium.
Dawn Orbiter Reaches Dwarf-Planet Ceres
The long-distance traveler has finally arrived at the first dwarf planet (and largest asteroid) yet studied by spacecraft.
Bright Spots on Ceres Intrigue Scientists
Incoming views of the asteroid belt's largest body reveal spots where ice from the interior might be exposed on the surface.
Venus and Mars Pair Tightly at Dusk
Earth's two closest planetary neighbors draw strikingly close together this week.
Tour February's Sky: Two Conjunctions
Some of the prettiest nighttime sights involve the close pairing of two solar-system bodies, and February features events with the Moon and Jupiter, then Venus and Mars.
Rosetta Reveals Much About Comet 67P
Once the Rosetta spacecraft arrived at Comet 67P/Churyumov-Gerasimenko last August, European scientists used an array of instruments to assess every nook and cranny of the remarkable two-lobed nucleus.
Catch Comet Finlay's Sudden Brightening
For the second time in as many months, the periodic comet 15P/Finlay has surged in brightness. Spot it soon — before the Moon interferes — using our exclusive sky charts.
Long-lost Beagle 2 Lander Found on Mars
It's been 11 years since the British-built Beagle 2 lander dropped to the Martian surface and disappeared without a trace. Now we know what happened to it.
Eta Carinae's Throbbing X-ray Pulse
When the massive, unstable southern star Eta Carinae sent a blast of X-rays into space last July, astronomers around the world were waiting and watching.
Give-and-Take Origin for Earth's Water?
Where, exactly, did our oceans come from? New research suggests that asteroids might have both delivered and removed lots of water — and that Earth itself might have locked it away deep inside.
Tour January's Sky: The Pleiades
Our downloadable monthly podcast offers highlights for stargazing in January, how to find the planets, and a special look at the Pleiades star cluster
ESA Bids Farewell to Venus Express
A highly successful spacecraft has ended its mission after returning nearly a decade of data on Earth's nearest planetary neighbor.
Earth's Water Likely Not From Comets
An early outcome from Rosetta's scrutiny of Comet 67P/Churyumov-Gerasimenko is that the isotopes in its water have distinctly different ratios than those on Earth.
