M32: Blue Stars in an Elliptical Galaxy
3.11.1999

Elliptical galaxies are known for their old, red stars. But is this old elliptical up to new tricks? In recent years, the centers of elliptical galaxies have been found to emit unexpectedly high amounts of blue and ultraviolet light.

The Stars of the Triangulum Galaxy
23.02.2019

Like grains of sand on a cosmic beach, stars of the Triangulum Galaxy are resolved in this sharp mosaic from the Hubble Space Telescope's Advanced Camera for Surveys (ACS). The inner region of the galaxy spanning over 17,000 light-years is covered at extreme resolution, the second largest image ever released by Hubble.

Dueling Bands in the Night
1.03.2022

What are these two bands in the sky? The more commonly seen band is the one on the right and is the central band of our Milky Way galaxy. Our Sun orbits...

At the Edge of NGC 891
26.05.2012

This sharp cosmic portrait features NGC 891. The spiral galaxy spans about 100 thousand light-years and is seen almost exactly edge-on from our perspective. In fact, about 30 million light-years distant in the constellation Andromeda, NGC 891 looks a lot like our Milky Way.

APOD: 2023 December 27 Б Rainbow Aurora over Icelandic Waterfall
27.12.2023

Yes, but can your aurora do this? First, yes, auroras can look like rainbows even though they are completely different phenomena. Auroras are caused by Sun-created particles being channeled into Earth's atmosphere by Earth's magnetic field, and create colors by exciting atoms at different heights.

APOD: 2023 February 15 Б Airglow Sky over France
15.02.2023

This unusual sky was both familiar and unfamiliar. The photographer's mission was to capture the arch of the familiar central band of our Milky Way Galaxy over a picturesque medieval manor. The surprise was that on this January evening, the foreground sky was found glowing in a beautiful but unfamiliar manner.

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.

Peculiar Galaxies of Arp 273
5.01.2017

The spiky stars in the foreground of this sharp cosmic portrait are well within our own Milky Way Galaxy. The two eye-catching galaxies lie far beyond the Milky Way, at a distance of over 300 million light-years. Their distorted appearance is due to gravitational tides as the pair engage in close encounters.

Messier Marathon
11.03.2000

Gripped by an astronomical spring fever, it's once again time for many amateur stargazers to embark on a Messier Marathon! The Vernal Equinox occurs March 20, marking the first day of Spring for the Northern Hemisphere.

APOD: 2024 October 2 Б The Large Magellanic Cloud Galaxy
2.10.2024

It is the largest satellite galaxy of our home Milky Way Galaxy. If you live in the south, the Large Magellanic Cloud (LMC) is quite noticeable, spanning about 10 degrees across the night sky, which is 20 times larger than the full moon towards the southern constellation of the dolphinfish (Dorado).