M20: The Trifid Nebula
31.03.1998

Unspeakable beauty and unimaginable bedlam can be found together in the Trifid Nebula. Also known as M20, this photogenic nebula is visible with good binoculars in the constellation of Sagittarius. The energetic processes of star formation create not only the colors but the chaos. The red-glowing gas results from high-energy light striking interstellar hydrogen gas.

The Colorful Clouds of Rho Ophiuchi
12.03.1996

The many spectacular colors of the Rho Ophiuchi (oh'-fee-yu-kee) clouds highlight the many processes that occur there. The blue regions shine primarily by reflected light. Blue light from the star rho Ophiuchi and nearby stars reflects more efficiently off this portion of the nebula than red light.

NGC 1700: Elliptical Galaxy and Rotating Disk
16.01.2003

In spiral galaxies, majestic winding arms of young stars and interstellar gas and dust rotate in a disk around a bulging galactic nucleus. Elliptical galaxies seem to be simpler, randomly swarming with old stars and lacking gas and dust.

Galaxy Wars: M81 versus M82
3.02.2016

In the lower left corner, surrounded by blue spiral arms, is spiral galaxy M81. In the upper right corner, marked by red gas and dust clouds, is irregular galaxy M82. This stunning vista shows these two mammoth galaxies locked in gravitational combat, as they have been for the past billion years.

APOD: 2025 July 13 Б Planetary Nebula Mz3: The Ant Nebula
13.07.2025

Why isn't this ant a big sphere? Planetary nebula Mz3 is being cast off by a star similar to our Sun that is, surely, round. Why then would the gas that is streaming away create an ant-shaped nebula that is distinctly not round?

The Cats Eye Nebula
24.03.2002

Three thousand light-years away, a dying star throws off shells of glowing gas. This image from the Hubble Space Telescope reveals the Cat's Eye Nebula to be one of the most complex planetary nebulae known.

M77: Spiral with a Strange Glow
10.09.1996

Why is M77 surrounded by an ultraviolet glow? M77, also called NGC 1068, appears at first sight to be a relatively normal barred spiral galaxy. But when photographed in the ultraviolet (UV), as shown above in false color, the galaxy sports an ultraviolet halo - shown as violet in the photograph.

Stars, Dust and Nebula in NGC 2170
28.02.2007

When stars form, pandemonium reigns. A textbook case is the star forming region NGC 2170. Visible above are red glowing emission nebulas of hydrogen, blue reflection nebulas of dust, dark absorption nebulas of dust, and the stars that formed from them.

APOD: 2024 January 29 Б The Pleiades: Seven Dusty Sisters
29.01.2024

The well-known Pleiades star cluster is slowly destroying part of a passing cloud of gas and dust. The Pleiades is the brightest open cluster of stars on Earth's sky and can be seen from almost any northerly location with the unaided eye.

Hot Stars in the Southern Milky Way
7.05.1999

Hot blue stars, red glowing hydrogen gas, and dark, obscuring dust clouds are strewn through this dramatic region of the Milky Way in the southern constellation of Ara (the Altar). About 4,000 light-years from Earth, the stars at the left are young, massive, and energetic.