The Hydra Cluster of Galaxies
16.04.2001

The Hydra Cluster of Galaxies contains well over 100 bright galaxies - but perhaps fewer galaxies than might be expected from its mass. Clusters of galaxies are the largest gravitationally bound objects in the universe.

Repairing Hubble
16.11.1995

The first Hubble Space Telescope (HST) servicing mission, STS-61, was one of the most complicated shuttle missions ever planned. Launched on December 2, 1993 in the Space Shuttle Endeavor, the astronauts were required to make 5 space walks to repair the HST. Astronaut F.

The 76 Meter Lovell Radio Telescope
8.03.1996

Jodrell Bank in England is the home of the Lovell Telescope one of the largest radio telescopes in the world. Completed in 1957 under the direction of Bernard Lovell, the 250 ft. diameter dish was the largest steerable radio telescope.

NGC 7331 and Beyond
27.07.2006

Spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier's famous 18th century catalog.

APOD: 2026 February 10 Б In Green Company: Aurora over Norway
10.02.2026

Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display.

The Perseus Cluster of Galaxies
15.08.1998

Here is one of the largest objects that anyone will ever see on the sky. Each of the fuzzy blobs in the above picture is a galaxy, together making up the Perseus Cluster, one of the closest clusters of galaxies.

Messier 77
10.05.2013

Face-on spiral galaxy M77 lies a mere 47 million light-years away toward the aquatic constellation Cetus. At that estimated distance, the gorgeous island universe is about 100 thousand light-years across. Also known...

Distant Supernova Dark Energy
4.04.2001

Light from a star that exploded over 10 billion light-years away is revealed in the panel at the lower right, a cosmic snapshot of the most distant supernova. The ancient stellar detonation was detected...

Globular Cluster M5
19.10.1995

The globular cluster M5, pictured above, contains roughly 100,000 stars. These stars formed together and are gravitationally bound. Stars orbit the center of the cluster, and the cluster orbits the center of our Galaxy. So far, about 160 globular clusters are known to exist in a roughly spherical halo around the Galactic center.

Arecibo: The Largest Telescope
29.11.1998

The Arecibo radio telescope is currently the largest single-dish telescope in the world. First opening in 1963, this 305 meter (1000 foot) radio telescope resides in a natural valley of Puerto Rico. The Arecibo telescope has been used for many astronomical research projects, including