X Ray Moon
2.09.2000

This x-ray image of the Moon was made by the orbiting ROSAT (Röntgensatellit) Observatory in 1990. In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray moon, the darker half of the moon, and the x-ray sky background.

Shell Game in the LMC
18.05.2006

An alluring sight in dark southern skies, the Large Magellanic Cloud (LMC) is seen here through a narrow filter that transmits only the red light of hydrogen atoms. Ionized by energetic starlight, a hydrogen atom emits the characteristic red H-alpha light as its single electron is recaptured and transitions to lower energy states.

NGC 6357: Stellar Wonderland
26.12.2016

For reasons unknown, NGC 6357 is forming some of the most massive stars ever discovered. This complex wonderland of star formation consists of numerous filaments of dust and gas surrounding huge cavities of massive star clusters. The intricate patterns are caused by complex interactions between interstellar winds, radiation pressures, magnetic fields, and gravity.

NGC 6357: The Lobster Nebula
7.02.2017

Why is the Lobster Nebula forming some of the most massive stars known? No one is yet sure. Near the more obvious Cat's Paw nebula on the upper right, the Lobster Nebula...

The Elephant's Trunk Nebula in Cepheus
1.08.2020

Like an illustration in a galactic Just So Story, the Elephant's Trunk Nebula winds through the emission nebula and young star cluster complex IC 1396, in the high and far off constellation of Cepheus. Also known as vdB 142, the cosmic elephant's trunk is over 20 light-years long.

APOD: 2024 April 15 Б The Cigar Galaxy from Hubble and Webb
15.04.2024

Something strange happened to this galaxy, but what? Known as the Cigar Galaxy and cataloged as M82, red glowing gas and dust are being cast out from the center. Although this starburst galaxy...

APOD: 2025 March 17 Б Thors Helmet
17.03.2025

Thor not only has his own day (Thursday), but a helmet in the heavens. Popularly called Thor's Helmet, NGC 2359 is a hat-shaped cosmic cloud with wing-like appendages. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across.

APOD: 2025 March 18 Б LDN 1235: The Shark Nebula
18.03.2025

There is no sea on Earth large enough to contain the Shark nebula. This predator apparition poses us no danger as it is composed only of interstellar gas and dust. Dark dust like that featured here is somewhat like cigarette smoke and created in the cool atmospheres of giant stars.

NGC 3603: X-Rays From A Starburst Cluster
24.01.2001

A mere 20,000 light-years from the Sun lies the NGC 3603 star cluster, a resident of the nearby Carina spiral arm of our Milky Way galaxy. Seen here in this recent false-color x-ray...

NGC 4414: A Telling Spiral
9.06.1999

How far away is this galaxy? Cosmologists the world over have been working hard to find out. Spiral galaxy NGC 4414 contains many Cepheid variable stars that oscillate in a way that allows astronomers to estimate their distance.