A Sky Full Of Hydrogen
13.01.2001

Interstellar space is filled with extremely tenuous clouds of gas which are mostly Hydrogen. The neutral hydrogen atom (HI in astronomer's shorthand) consists of 1 proton and 1 electron. The proton and electron spin like tops but can have only two orientations; spin axes parallel or anti-parallel.

The Small Cloud of Magellan
17.06.2005

Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two celestial wonders easily visible for southern hemisphere skygazers are known as the Clouds of Magellan.

Star Forming Region NGC 6357
20.12.2006

For reasons unknown, NGC 6357 is forming some of the most massive stars ever discovered. Near the more obvious Cat's Paw nebula, NGC 6357 houses the open star cluster Pismis 24, home to these tremendously bright and blue stars.

X Ray Stars of Orion
6.10.2007

The stars of Orion shine brightly in visible light in planet Earth's night sky. The constellation harbors the closest large stellar nursery, the Great Nebula of Orion, a mere 1,500 light-years away.

The Center of Centaurus A
7.11.2010

A fantastic jumble of young blue star clusters, gigantic glowing gas clouds, and imposing dark dust lanes surrounds the central region of the active galaxy Centaurus A. This mosaic of Hubble Space Telescope images taken in blue, green, and red light has been processed to present a natural color picture of this cosmic maelstrom.

Merging NGC 2623
19.10.2012

NGC 2623 is really two galaxies that are becoming one. Seen to be in the final stages of a titanic galaxy merger, the pair lies some 300 million light-years distant toward the constellation Cancer.

The Gegenschein Over Chile
2.12.2012

Is the night sky darkest in the direction opposite the Sun? No. In fact, a rarely discernable faint glow known as the gegenschein (German for "counter glow") can be seen 180 degrees around from the Sun in an extremely dark sky. The gegenschein is sunlight back-scattered off small interplanetary dust particles.

M42: Inside the Orion Nebula
8.04.2014

The Great Nebula in Orion, an immense, nearby starbirth region, is probably the most famous of all astronomical nebulas. Here, glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1500 light-years away.

A Sagittarius Triplet
10.08.2015

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 large nebula left of center, and colorful M20 on the right.

NGC 4372 and the Dark Doodad
10.09.2015

The delightful Dark Doodad Nebula drifts through southern skies, a tantalizing target for binoculars in the constellation Musca, The Fly. The dusty cosmic cloud is seen against rich starfields just south of the prominent Coalsack Nebula and the Southern Cross.