SUNSET: 
The Coolest Stars Ever Found?
Astronomers have found what could be the first-ever members of a new stellar class — "stars" with surface temperatures lower than that of a hot cup of coffee.
Best-yet Value for Universe's Expansion
A new study with the Hubble Space Telescope pins down the universe's expansion rate with unprecedented accuracy.
Mercury at Its Evening Highest
This week, Mercury reaches its highest in the evening sky for observers in the Northern Hemisphere.
The March 19th "Supermoon": Hardly Super
Saturday's full Moon is indeed the closest and biggest in 18 years. But not by enough to notice.
Messenger: Mercury's New Moon
The fleet-footed planet of the ancients has a new companion — a NASA spacecraft that will now call it home after a convoluted, 6½-year-long, 5-billion-mile interplanetary cruise.
What Makes Iapetus So Weird?
Now that scientists have puzzled out this moon's yin-yang appearance, they're tackling the cause of its out-of-round shape, slow spin, and bizarre equatorial ridge.
Is Water Flowing on Mars?
Spacecraft images are keeping an eye on little surface flows on Mars that show up in midsummer, then fade over time. It's the strongest suggestion yet that the Red Planet can get wet.
Inside Sky & Telescope's May 2011 Issue
Sky & Telescope's May 2011 issue is now available to digital subscribers.
Watch a Star Wink Out on Sunday
On Sunday, March 13th, not long after sunset, a 3rd-magnitude star will disappear suddenly as it's covered by the dark edge of the Moon for parts of eastern North America.
Remembering James Elliot, 1943–2011
The co-discoverer of Uranus's rings and Pluto's atmosphere has passed away at age 67.
Best Mercury of 2011
Mercury's best evening apparition of 2011 for Northern Hemisphere observers takes place this March. And with Jupiter to point the way, Mercury is unusually easy to locate from March 12–18.
Video: Tips on Orion's 3-inch Altaz Reflector
If you've bought Orion's 3-inch SpaceProbe Altazimuth Reflector, or are thinking of doing so, take a look at this video for some tips on how to use the scope.
Game Plan for NASA's Planetary Missions
If you had billions of dollars to spend on interplanetary spacecraft, which ones would you choose and why? After an exhaustive, two-year assessment, a blue-ribbon panel turned over its top picks to NASA.
The Four-Planet Dance of 2011
Every morning in May 2011, just before sunrise, four planets combine to form fascinating and ever-changing patterns.
Kepler Finds Planets in Tight Dance
It can get pretty crowded in the solar systems discovered by NASA's Kepler observatory. In one case, four candidate worlds are locked in a tight orbital dance.
A New Take on the Spotless Sun
A trio of researchers believe a slow-moving conveyor belt between the Sun's equator and its poles is responsible for the recent years-long absence of sunspots.
Another Photometry Chat Saturday, March 19th
The AAVSO digital-camera photometry team will be holding another chat session at 11 a.m. EST Saturday, March 19th, to answer questions about their article in the April 2011 issue of Sky & Telescope.
Sky & Telescope: All 70 Years
A unified index for all 68 years (and 2 months) of Sky & Telescope is now available online.
Double Whammy on Mars
On January 10th, NASA's Mars Reconnaissance Orbiter spotted twin craters joined at the rim — the consequence of equal-size halves of a single object striking the planet together.
Leif J. Robinson, 1939–2011
All of us who work at Sky & Telescope are deeply saddened to receive news this morning that our long-time editor in chief, Leif J. Robinson, has passed away at the age of 71.
