M33: Triangulum Galaxy
20.12.2012

The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way.

The Boomerang Nebula in Polarized Light
14.09.2005

Why did the Boomerang Nebula form? The symmetric cloud dubbed the Boomerang appears to have been created by a high-speed wind of gas and dust blowing from an aging central star at speeds of nearly 600,000 kilometers per hour.

GRB Fireball Persists
17.09.1997

It's still there. The optical counterpart to the instantly famous gamma-ray burst (GRB) that occurred last February 28th has faded - but not completely. The astronomical community had waited patiently for months...

NGC 4565: Needle Galaxy
17.06.1999

Presenting a sleek needle-like profile the magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Its core of stars bulges from the centre of a thin disk of spiral arms and dust. The core appears to be cut sharply by dust lanes to dramatic effect in this composite image.

NGC 6934 from Gemini North
30.06.1999

What's going on near the center of globular cluster NGC 6934? The blur caused by the Earth's atmosphere has prevented astronomers from discerning individual stars in this unusual environment. Telescopes in space can help, but the new Gemini North telescope took the above picture from the ground.

Gibbous Europa
15.12.2013

Although the phase of this moon might appear familiar, the moon itself might not. In fact, this gibbous phase shows part of Jupiter's moon Europa. The robot spacecraft Galileo captured this image mosaic during its mission orbiting Jupiter from 1995 - 2003.

APOD: 2025 August 25 Б The Meteor and the Star Cluster
25.08.2025

Sometimes even the sky surprises you. To see more stars and faint nebulosity in the Pleiades star cluster (M45), long exposures are made. Many times, less interesting items appear on the exposures that were not intended -- but later edited out.

ESO 184 G82: and the Supernova Gamma Ray Burst Connection
28.02.2002

Modern astronomers keep a long list of things that go bump in the night. Near the top are supernovae - the death explosions of massive stars, and gamma-ray bursts - the most powerful explosions seen across the Universe.

A Year of New Perspectives
28.12.1999

Fittingly, 1999 saw a decade of astronomical discoveries to an end with portents of things to come - embodied in new spacecraft, telescopes, and perspectives to explore the distant Universe across the electromagnetic spectrum. X-ray astronomy in particular will likely flourish in coming

All of Mercury
12.06.2013

For the first time, the entire surface of planet Mercury has been mapped. Detailed observations of the innermost planet's surprising crust have been ongoing since the robotic MESSENGER spacecraft first passed Mercury in 2008 and began orbiting in 2011.