Sagittarius Triplet
4.08.2007

These three bright nebulae are often featured in telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the nebula below and right of center, and colorful M20 at the upper right.

A Lunar Eclipse on Solstice Day
20.12.2010

Sometime after sunset tonight, the Moon will go dark. This total lunar eclipse, where the entire Moon is engulfed in the shadow of the Earth, will be visible from all of North America, while the partial phase of this eclipse will be visible throughout much of the rest of the world.

Distortion from a Distant Cluster
23.08.2001

This stunning color deep sky view toward the constellation Pisces was made with data from a fast, sensitive, digital detector known as the Big Throughput Camera operating at Cerro Tololo Inter-American Observatory in Chile.

APOD: 2024 April 24 Б Dragons Egg Bipolar Emission Nebula
24.04.2024

How did a star form this beautiful nebula? In the middle of emission nebula NGC 6164 is an unusually massive star. The central star has been compared to an oyster's pearl and an egg protected by the mythical sky dragons of Ara.

Conjunction Over Reunion Island
7.03.2012

You don't have to be on Reunion Island to see this week's planetary conjunction. Only if you want to see this picturesque seascape as well. To see the conjunction from just about anywhere in the world, look to the west after sunset.

A Phoenix Aurora over Iceland
16.03.2016

All of the other aurora watchers had gone home. By 3:30 am in Iceland, on a quiet night last September, much of that night's auroras had died down. Suddenly though, a new burst of particles streamed down from space, lighting up the Earth's atmosphere once again.

Behind Betelgeuse
11.05.2020

What's behind Betelgeuse? One of the brighter and more unusual stars in the sky, the red supergiant star Betelgeuse can be found in the direction of famous constellation Orion. Betelgeuse, however, is actually...

Simeis 147: Supernova Remnant
9.10.2012

It's easy to get lost following the intricate filaments in this detailed mosaic image of faint supernova remnant Simeis 147 (S147). Also cataloged as Sh2-240, it covers nearly 3 degrees or 6 full moons on the sky. That's about 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years.

Annapurna Star Trails
28.11.2009

In myth, Atlas holds up the heavens. But in this moonlit mountainscape, peaks of the Himalayan Annapurna Range appear to prop up the sky as seen from Ghandruk, Nepal. From left to right the three main peaks are Annapurna South (7,219 meters), Hiunchuli (6,441 metes), and Machapuchare (6,995 meters).

The Average Color of the Universe
1.11.2009

What color is the universe? More precisely, if the entire sky was smeared out, what color would the final mix be? This whimsical question came up when trying to determine what stars are commonplace in nearby galaxies. The answer, depicted above, is a conditionally perceived shade of beige.