The Radio Sky: Tuned to 408MHz
3.04.1999

Tune your radio telescope to 408MHz (408 million cycles per second) and check out the Radio Sky! You should find that frequency on your dial somewhere between US broadcast television channels 13 and 14.

SOHO s Uninterrupted View of the Sun
1.12.2005

Launched ten years ago this week, SOHO (the SOlar and Heliospheric Observatory) still enjoys an uninterrupted view of the Sun. Twelve sungazing instruments on board the spacecraft have explored the Sun's internal structure...

51 Pegasi: A New Planet Discovered
1.12.1995

Are we alone in the universe? Do other stars have planets too? Humanity took one step closer to answering these questions in October 1995 when it was announced that the star 51 Pegasi harbors at least one planet.

Red Saturn
10.02.2005

This strange, false-color image of otherwise familiar planet Saturn shows temperature changes based on thermal infrared emission in the gas giant's atmosphere and rings. Recorded from the Keck I telescope on Mauna Kea, the sharp, ground-based picture of Saturn's southern hemisphere is a mosaic of 35 images.

Jupiter from the Stratosphere
3.06.2010

SOFIA, the Stratospheric Observatory for Infrared Astronomy, captured its "first light" images on May 26, from an altitude of 35,000 feet. While flying above most of planet Earth's infrared-absorbing water vapor, SOFIA's premier infrared views of the cosmos included this remarkable false-color image (right panel) of Jupiter.

Gamma Ray Bursts from the Unknown
23.11.1996

Gamma Ray Bursts (GRBs) pose one of the greatest mysteries of modern astronomy. About once a day, the gamma-ray sky lights up with a spectacular explosion. No one knows what causes these explosions or even how far away they are.

Galaxy Group HCG 87
16.07.2005

Posing for this cosmic family photo are the galaxies of HCG (Hickson Compact Group) 87, about four hundred million light-years distant toward the amphibious constellation Capricornus. The large edge-on spiral near picture center...

Sun with Solar Flare
13.04.2013

This week the Sun gave up its strongest solar flare so far in 2013, accompanied by a coronal mass ejection (CME) headed toward planet Earth. A false-color composite image in extreme ultraviolet light from the Solar Dynamics Observatory captures the moment, recorded on April 11 at 0711 UTC. The flash, a moderate, M6.

Eclipsed in Southern Skies
1.10.2015

This stunning panorama in southern skies was recorded on the colorful night of September 27/28 from Carngegie Las Campanas Observatory. A diffuse glow and dark rifts of the central Milky Way hang over domes of the twin 6.5 meter Magellan telescopes. But most eye-catching is the deep red glow of the Moon.

APOD: 2026 March 29 Б A Message from Earth
29.03.2026

What are these Earthlings trying to tell us? The featured message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of an upgrade to the Arecibo Observatory - then the largest single radio telescope in the world - a string of 1's and 0's representing the diagram was sent.