Moon and Planets Sky
26.03.2004

Look up into the sky tonight and without a telescope or binoculars you might have a view like this one of Moon, planets and stars. The lovely photo was taken on March 23rd, and captures the crescent Moon on the horizon with Venus above it. Both brilliant celestial bodies are over-exposed.

Hidden Galaxy IC 342
18.07.2013

Similar in size to large, bright spiral galaxies in our neighborhood, IC 342 is a mere 10 million light-years distant in the long-necked, northern constellation Camelopardalis. A sprawling island universe, IC 342 would otherwise...

The Sand Dunes of Titan
10.08.2010

Why do some sand dunes on Titan appear backwards? Central Titan, it turns out, is covered by sand, some of which appears strange. Images from the Cassini spacecraft currently orbiting Saturn have uncovered long rows of huge sand dunes near Titan's equator that rise as high as 300 meters.

Highlights of the Summer Sky
5.06.2017

What's up in the sky this summer? The featured graphic gives a few highlights for Earth's northern hemisphere. Viewed as a clock face centered at the bottom, early summer sky events fan out toward the left, while late summer events are projected toward the right.

APOD: 2025 September 7 Б All the Water on Planet Earth
7.09.2025

How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth's surface, these oceans are shallow compared to the Earth's radius.

Ecliptic New Zealand
10.07.2010

Four bright celestial beacons and a faint triangle of light follow the plane of the ecliptic as it arcs high through this southern hemisphere night skyscape. Seen on a July winter night from Lake...

Close Comet and the Milky Way
25.03.2016

Comet 252P/Linear's lovely greenish coma is easy to spot in this expansive southern skyscape. Visible to the naked eye from the dark site near Flinders, Victoria, Australia, the comet appears tailless. Still, its surprisingly bright coma spans about 1 degree, posed here below the nebulae, stars, and dark rifts of the Milky Way.

APOD: 2023 June 13 Б Moons Across Jupiter
13.06.2023

Jupiter's moons circle Jupiter. The featured video depicts Europa and Io, two of Jupiter's largest moons, crossing in front of the grand planet's Great Red Spot, the largest known storm system in our Solar System.

Enceladus and the Search for Water
10.03.2006

Based on data from Cassini spacecraft instruments, researchers are now arguing that liquid water reservoirs exist only tens of meters below the surface of Saturn's small (500 kilometer diameter) but active moon Enceladus. The exciting new results center around towering jets and plumes of material erupting from the moon's surface.

Solar System Portrait
14.02.2013

On another Valentine's Day (February 14, 1990), cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back to make this first ever family portrait of our Solar System. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane.