Light Echoes from V838 Mon
17.03.2013

What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded.

Flying over Planet Earth
27.09.2011

Have you ever dreamed of flying high above the Earth? Astronauts visiting the International Space Station do this every day, circling our restless planet twice every three hours. A dramatic example of their view was compiled in the above time-lapse video from images taken earlier this month.

The Pleiades Deep and Dusty
25.02.2014

The well known Pleiades star cluster is slowly destroying part of a passing cloud of gas and dust. The Pleiades is the brightest open cluster of stars on Earth's sky and can be seen from almost any northerly location with the unaided eye.

A Window to the Once Secret Sky
13.04.2005

If there was a window nearby to the distant universe -- would you look through it? Quite possibly, there is, in the form of a small telescope. A local skykeeper could be a relative or a stranger and is frequently proud to show off the sky free of charge.

Prometheus Remastered
5.04.2010

What does Saturn's shepherd moon Prometheus really look like? The raw images from the robotic Cassini spacecraft's January flyby of the small moon showed tantalizing clues on grainy images, but now that the Cassini team has digitally remastered these images, many more details have come out.

The Climber and the Eclipse
6.09.2017

What should you do if your rock climbing picture is photobombed by a total eclipse of the Sun? Rejoice -- because your planning paid off. After months of considering different venues, and a week...

Eclipsosaurus Rex
7.10.2017

We live in an era where total solar eclipses are possible because at times the apparent size of the Moon can just cover the disk of the Sun. But the Moon is slowly moving away from planet Earth. Its distance is measured to increase about 1.5 inches (3.8 centimeters) per year due to tidal friction.

The Sombrero Galaxy from Hubble
26.07.2015

Why does the Sombrero Galaxy look like a hat? Reasons include the Sombrero's unusually large and extended central bulge of stars, and dark prominent dust lanes that appear in a disk that we see nearly edge-on. Billions of old stars cause the diffuse glow of the extended central bulge.

South Polar Vortex Discovered on Titan
24.07.2012

What's happening over the south pole of Titan? A vortex of haze appears to be forming, although no one is sure why. The above natural-color image shows the light-colored feature. The vortex was found on images taken last month when the robotic Cassini spacecraft flew by the unusual atmosphere-shrouded moon of Saturn.

APOD: 2025 April 9 Б HH 49: Interstellar Jet from Webb
9.04.2025

What's at the tip of this interstellar jet? First let's consider the jet: it is being expelled by a star system just forming and is cataloged as Herbig-Haro 49 (HH 49). The star system expelling this jet is not visible -- it is off to the lower right.