Generations of Stars in W5
29.08.2008

Giant star forming region W5 is over 200 light-years across and about 6,500 light-years away in the constellation Cassiopeia. W5's sculpted clouds of cold gas and dust seem to form fantastic shapes in this impressive mosaic of infrared images from the Spitzer Space Telescope.

Spitzer s M101
29.12.2009

Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way Galaxy.

HESS Telescopes Explore the High Energy Sky
7.01.2019

They may look like modern mechanical dinosaurs but they are enormous swiveling eyes that watch the sky. The High Energy Stereoscopic System (H.E.S.S.) Observatory is composed of four 12-meter reflecting-mirror telescopes surrounding a larger telescope housing a 28-meter mirror.

APOD: 2023 July 30 Б Spiral Aurora over Icelandic Divide
29.07.2023

Admire the beauty but fear the beast. The beauty is the aurora overhead, here taking the form of a great green spiral, seen between picturesque clouds with the bright Moon to the side and stars in the background.

Comet Hyakutake's Past and Future
22.03.1996

The above false-color picture of Comet Hyakutake taken just two days ago shows its rapidly developing tail. The comet now has a substantial coma with a bright center, lending it a dramatic eye-like appearance. This is not Comet Hyakutake's first visit to the inner Solar System.

M27: Not a Comet
26.08.2010

While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were definitely not comets. This is number 27 on his now famous not-a-comet list.

The Rippled Red Ribbons of SNR 0509
24.01.2011

What is causing the picturesque ripples of supernova remnant SNR 0509-67

Wonder and Mystery above the Very Large Telescopes
9.05.2011

What's that bright orange dot above the large telescope on the right? Even seasoned sky enthusiasts might ponder the origin of the orange orb seen by scrolling across this panoramic image, taken last December. Perhaps identifying known objects will help.

APOD: 2023 September 6 Б HESS Telescopes Explore the High Energy Sky
5.09.2023

They may look like modern mechanical dinosaurs, but they are enormous swiveling eyes that watch the sky. The High Energy Stereoscopic System (H.E.S.S.) Observatory is composed of four 12-meter reflecting-mirror telescopes surrounding a larger telescope housing a 28-meter mirror.

APOD: 2026 May 21 Б A Collision of Galaxy Clusters
20.05.2026

This big beautiful spiral shines in X-ray light. It is about 20 times larger than our Galaxy. It belongs to Abell 2029, a galaxy cluster one billion light-years away. (To see only the galaxies...