SUNSET: 
The United Arab Emirates' Hope Enters Orbit Around Mars
The United Arab Emirates Hope orbiter is the first in a series of spacecraft arriving at the Red Planet in the next week.
Tree Rings Help Reconstruct a Millennium of the Sun's Activity
Astronomers are using tree rings as a historical record of solar activity — and they've found that the Sun was much more active in the past.
This Week's Sky at a Glance, February 5 – 13
The sky's biggest asterism — at least the biggest one widely recognized — is the Winter Hexagon. It fills the sky toward the east and south these evenings. Start with brilliant Sirius at its bottom. . .
Our Tiny Galactic Neighbor Hosts Ancient Stars
New observations show ancient stars lining the edges of the ultra-faint dwarf galaxy Tucana II, a tiny satellite of the Milky Way.
Second Earth Trojan Asteroid Discovered
A recently discovered asteroid appears to be an Earth Trojan, orbiting a gravitationally stable area with only one other known occupant.
Planets and Comets Can't Hide from SOHO's Eye
With the help of the Solar Heliospheric Observatory you can not only keep track of the planets in the daytime sky but maybe even discover a comet.
Green Bank Tests New Planetary Radar
A newly installed planetary radar system on the Green Bank Radio Telescope will probe the solar system in detail.
February: The Hare & Unicorn
When you step outside to admire the crisp, starlit night sky on February evenings, bring along our Sky Tour astronomy podcast to learn which stars and constellations are overhead. Here’s a preview of what you'll see.
Meet Castor, Six Stars in One
Castor, a prime ornament of the Gemini constellation and one of the brightest stars in the sky, is actually a system of stars with six unique members.
This Week's Sky at a Glance, January 29 – February 6
Once the night is fully dark, spot the equilateral Winter Triangle in the southeast. Sirius is its brightest and lowest star. Betelgeuse stands above Sirius by about two fists at arm's length. To the left of their midpoint is Procyon. Compare their colors!
Measuring Solar Eruptions with a Rare Alignment
New analysis of a coronal mass ejection detected by the alignment of two spacecraft reveals that it experienced erosion and restructuring as it traveled.
Solar and Lunar Eclipses in 2021
Four eclipses occur in 2021, with annular and total solar eclipses alternating between total and not-quite-total lunar eclipses.
Astronomers Spot Galaxies Clustering in Early Universe
Astronomers have discovered a cluster of galaxies coming together just 770 million years after the Big Bang.
What New Horizons Found in Deep Space — And Why It Matters
NASA’s mission to the outer solar system has found more light than expected. That could mean more galaxies in the visible universe than we thought— or less, depending on who you talk to.
Beyond Starlink: The Satellite Saga Continues
SpaceX has placed more than 1,000 Starlinks in orbit, and other companies are following suit. Here's the latest on what's being done to protect astronomy.
Starlink Satellites Are Fainter Now — But Still Visible
Measurements of Starlink's "VisorSat" show SpaceX has succeeded in making a less reflective satellite. But it's still visible from dark-sky areas.
This Week's Sky at a Glance, January 22 – 30
Right after dark, face east and look very high. The bright star there is Capella, the Goat Star. To the right of it, by a couple of finger-widths at arm's length, is a small, narrow triangle of 3rd- and 4th-magnitude stars known as "the Kids." Though they're not exactly eye-grabbing, they form a never-forgotten asterism with Capella.
China's Chang'e 5 Probe Heads Sunward
China’s Chang’e 5 spacecraft helped deliver samples from the Moon to Earth. Now it’s heading for an extended mission to observe the Sun.
Comet Watch 2021
If you own an 8-inch or larger telescope you might see more than a dozen new and returning comets this year, including one potential naked-eye candidate.
NASA Extends Juno, InSight Missions
NASA has granted two key planetary missions extensions, so InSight and Juno will continue to return data from Mars and Jupiter, respectively, for years to come.
