Aurora over Sweden
3.05.2016

It was bright and green and stretched across the sky. This striking aurora display was captured last month just outside of жstersund, Sweden. Six photographic fields were merged to create the featured panorama spanning almost 180 degrees. Particularly striking aspects of this aurora include its sweeping arc-like shape and its stark definition.

The Prague Astronomical Clock
7.11.2017

In the center of Prague there's a clock the size of a building. During the day, crowds gather to watch the show when it chimes in a new hour. The Prague Astronomical Clock...

Fear and Dread: The Moons of Mars
30.10.2020

On Halloween fear and dread will stalk your night skies, also known as Phobos and Deimos the moons of Mars. The 2020 opposition of Mars was on October 13, so the Red Planet will still rise shortly after sunset.

M51: The Whirlpool Galaxy
2.09.2021

Find the Big Dipper and follow the handle away from the dipper's bowl until you get to the last bright star. Then, just slide your telescope a little south and west and you'll come upon this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog.

Blue Marble Earth
6.02.2022

Welcome to planet Earth, the third planet from a star named the Sun. The Earth is shaped like a sphere and composed mostly of rock. Over 70 percent of the Earth's surface is water. The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen.

Barred Spiral Galaxy NGC 1300
16.10.2022

Across the center of this spiral galaxy is a bar. And at the center of this bar is smaller spiral. And at the center of that spiralбis a supermassiveбblack hole.б This all happens...

Structure in the Tail of Comet 12P/Pons Brooks
16.02.2024

Heading for its next perihelion passage on April 21, Comet 12P/Pons-Brooks is growing brighter. The greenish coma of this periodic Halley-type comet has become relatively easy to observe in small telescopes. But the bluish...

Tycho Brahe Measures the Sky
7.01.2001

Tycho Brahe was the most meticulous astronomical observer of his time. Brahe, who lived between 1546 and 1601, set out to solve the day's most pressing astronomical problem: to determine whether the Earth or the Sun was at the center of the Solar System.

Gamma-ray Burster
18.12.1997

Gamma-ray bursts seem to be the most powerful explosions in the Universe. Yet their sources continue to elude researchers who stand in awe and frustration at the bursts' transient, enigmatic behavior. The blinking gif above illustrates the latest hard-won result in the quest to identify and understand the nature of the bursters.

IC 4628: The Prawn Nebula
20.10.2006

South of Antares, in the tail of the nebula-rich constellation Scorpius, lies emission nebula IC 4628. Nearby hot, massive stars, millions of years young, radiate the nebula with invisible ultraviolet light, stripping electrons from atoms. The electrons eventually recombine with the atoms to produce the visible nebular glow.