APOD: 2026 August 4 Б Curious Cometary Knots in the Helix Nebula
3.08.2026

What causes unusual knots of gas and dust in planetary nebulas? Seen also in the Ring Nebula, the Dumbbell Nebula and NGC 2392, the knots' existence was not initially predicted, and their origins are still not well understood.

An Orion Deep Field
14.01.2004

Adrift 1,500 light-years away in one of the night sky's most recognizable constellations, the glowing Orion Nebula and the dark Horsehead Nebula are contrasting cosmic vistas. They both appear in this stunning composite digital image assembled from over 20 hours of data that includes exposures filtered to record emission from hydrogen atoms.

NGC 4631: The Whale Galaxy
22.01.2004

NGC 4631 is a big beautiful spiral galaxy seen edge-on only 25 million light-years away towards the small northern constellation Canes Venatici. This galaxy's slightly distorted wedge shape suggests to some a cosmic herring and to others the popular moniker of The Whale Galaxy.

M81 and M82: GALEX Full Field
29.12.2004

Intriguing galaxy pair M81 and M82 shine in this full-field view from the orbiting GALEX observatory. GALEX - the Galaxy Evolution Explorer - scans the cosmos in ultraviolet light, a view that follows star formation and galaxy evolution through the Universe.

G21.5-0.9: A Supernova s Cosmic Shell
21.04.2005

The picture is lovely, but this pretty cosmic shell was produced by almost unbelievable violence - created when a star with nearly 20 times the mass of the sun blasted away its outer layers in a spectacular supernova explosion.

A Nearby Supernova in M51
19.07.2005

One of the nearest supernovas of recent years was discovered late last month in the bright nearby galaxy M51. It is visible on the right of the above before and after images of the picturesque spiral. Can you spot it?

A Meteor Shower Fireball Movie
12.08.2005

Go outside tonight and see a celestial light show -- the later the better. Tonight is the peak of the month-long Perseid Meteor Shower. Although visible every year at this time, the Perseids are expected to appear particularly active this year due to the relative absence of glare from the Moon during the peak.

Crab Nebula Mosaic from HST
1.12.2005

The Crab Nebula is cataloged as M1, the first object on Charles Messier's famous list of things which are not comets. In fact, the cosmic Crab is now known to be a supernova remnant, an expanding cloud of debris from the death explosion of a massive star.

GLIMPSE the Milky Way
15.12.2005

Scroll right and gaze through the dusty plane of our Milky Way Galaxy in infrared light. The cosmic panorama is courtesy of the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) project and the Spitzer Space Telescope.

M81 in Ursa Major
27.04.2007

One of the brightest galaxies in planet Earth's sky and similar in size to the Milky Way, big, beautiful spiral M81 lies 11.8 million light-years away in the northern constellation Ursa Major. This...