APOD: 2025 April 22 Б Terminator Moon: A Moonscape of Shadows
22.04.2025

What's different about this Moon? It's the terminators. In the featured image, you can't directly see any terminator -- the line that divides the light of day from the dark of night. That's because the featured image is a digital composite of many near-terminator lunar strips over a full Moon.

A Gallery of Gravitational Mirages
1.06.1999

The deeper you peer into the universe, the harder it is to see straight. The reason is that distant galaxies act as gravitational lenses, deflecting light that passes nearby. These deflections result in the distortion of background sources, and in some cases the creation of multiple images.

HR 4796A: A Recipe for Planets
22.04.1998

Two hundred and twenty light years from Earth, planets are forming. Recent observations of the binary star system HR 4796 have shown that one of the stars is surrounded by a dusty gaseous disk. This disk is of the right size, age, and density for dust pellets to accrete surrounding matter.

White Rock Fingers on Mars
13.05.2002

What caused this unusual white rock formation on Mars? Intrigued by the possibility that they could be salt deposits left over as an ancient lakebed dried-up, detailed studies of these fingers now indicate a more mundane origin: volcanic ash. Studying the exact color of the formation indicated the volcanic origin.

The Water Vapor Channel
12.10.1996

What alien planet's bizarre landscape lurks below these fiery-looking clouds? It's only Planet Earth, of course -- as seen on the Water Vapor Channel. Hourly, images like this one (shown in false color) are brought to you by the orbiting GOES 8 satellite's multi-channel imager.

The Bubble Nebula from NOAO
17.06.2003

It's the bubble versus the cloud. NGC 7635, the Bubble Nebula, is being pushed out by the stellar wind of massive central star BD+602522. Next door, though, lives a giant molecular cloud, visible above to the lower right.

In the Center of NGC 604
5.03.1997

Stars are sometimes born in the midst of chaos. About 3 million years ago in the nearby galaxy M33, a large cloud of gas spawned dense internal knots which gravitationally collapsed to form stars. But NGC 604 was so large, it could form enough stars to make a globular cluster.

A Cerro Tololo Sky
13.03.2004

High atop a Chilean mountain lies one of the premier observatories of the southern sky: the Cerro Tololo Inter-American Observatory (CTIO). Pictured above is the dome surrounding one of the site's best known instruments, the 4-meter Blanco Telescope.

NGC 3132: The Eight Burst Nebula
6.02.2005

It's the dim star, not the bright one, near the center of NGC 3132 that created this odd but beautiful planetary nebula. Nicknamed the Eight-Burst Nebula and the Southern Ring Nebula, the glowing gas originated in the outer layers of a star like our Sun.

December Moon Meets Evening Star
9.12.2005

If you've been outdoors near sunset, then you've probably noticed Venus low in the west as the brilliant evening star. Sometimes mistaken for a tower light near the horizon, Venus is the third brightest celestial beacon, after the Sun and Moon, in planet Earth's sky.