APOD: 2024 February 28 Б Shades of Night
28.02.2024

How does the sky turn dark at night? In stages, and with different characteristic colors rising from the horizon. The featured image shows, left to right, increasingly late twilight times after sunset in 20 different vertical bands. The picture was taken last month in Syracuse, Sicily, Italy, in the direction opposite the Sun.

Seven Dusty Sisters
13.04.2007

Hurtling through a cosmic dust cloud a mere 400 light-years away, the lovely Pleiades or Seven Sisters star cluster is well-known in astronomical images for its striking blue reflection nebulae. At visible wavelengths...

Steep Cliffs on Mars
1.07.2007

Vertical cliffs of nearly two kilometers occur near the North Pole of Mars. Also visible in the above image of the Martian North Polar Cap are red areas of rock and sand, white areas of ice, and dark areas of unknown composition but hypothesized to be volcanic ash.

The 60 inch Reflector
13.12.2008

On the night of December 13, 1908, 100 years ago today, the 60-inch diameter reflecting telescope of Mount Wilson Observatory was first tested on the stars. It became the first successful large reflecting telescope.

Alpine Conjunction
2.01.2009

Did you see it? The last conjunction of Moon and bright planets in 2008 featured a young crescent Moon and brilliant Venus in the west after sunset on December 31st. Seen here in dark, clear, mountain air from Mönichkirchen, Austria, are the two celestial beacons that dominate planet Earth's night sky.

Shuttle Reentry Streak from Orbit
1.08.2011

What's that strange bright streak? It is the last image ever of a space shuttle from orbit. A week and a half ago, after decoupling from the International Space Station, the Space Shuttle Atlantis fired its rockets for the last time, lost its orbital speed, and plummeted back to Earth.

New Horizons
22.06.2015

In three weeks, the robotic New Horizons spacecraft will reach Pluto. As the featured video makes clear, though, humanity has been on an unprecedented epoch of robotic exploration of our Solar System's planets for the past half century.

Shadowrise and Sunset
1.06.2017

The road tracking through this stunning 360 degree view crosses a remote mountain area of Jämtland, Sweden, planet Earth. A 3x8 mosaic of still images, the panorama was taken on May 3rd from a small drone 200 meters above the ground.

Eight Planets and New Solar System Designations
28.08.2006

How many planets are in the Solar System? This popular question now has a new formal answer according the International Astronomical Union (IAU): eight. Last week, the IAU voted on a new definition for planet and Pluto did not make the cut.

How to Identify that Light in the Sky
9.06.2014

What is that light in the sky? Perhaps one of humanity's more common questions, an answer may result from a few quick observations. For example -- is it moving or blinking?