APOD: 2024 March 26 Б Comet Pons Brooks Ion Tail
26.03.2024

Comet Pons-Brooks has quite a tail to tell. First discovered in 1385, this erupting dirty snowball loops back into our inner Solar System every 71 years and, this time, is starting to put on a show for deep camera exposures.

Saturns Rings from the Other Side
9.06.2008

What do Saturn's rings look like from the other side? From Earth, we usually see Saturn's rings from the same side of the ring plane that the Sun illuminates them. Geometrically...

Atlantis and Hubble Side by Side
16.05.2009

On Wednesday, May 13, two, tiny, fast moving spots crossed an otherwise featureless solar disk. Not sunspots though, the dark blemishes were silhouettes of the shuttle orbiter Atlantis and the Hubble Space Telescope side by side.

Iridescent Clouds over Thamserku
8.07.2014

Why would a cloud appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size.

ISS and Mercury Too
13.05.2016

Transits of Mercury are relatively rare. Monday's leisurely 7.5 hour long event was only the 2nd of 14 Mercury transits in the 21st century. If you're willing to travel, transits of the International Space Station can be more frequent though, and much quicker.

In the Heart of the Heart Nebula
14.02.2018

What's that inside the Heart Nebula? First, the large emission nebula dubbed IC 1805 looks, in whole, like a human heart. It's shape perhaps fitting of the Valentine's Day, this heart glows brightly in red light emitted by its most prominent element: hydrogen.

The Last Days of Venus as the Evening Star
6.01.2022

That's not a young crescent Moon posing behind cathedral towers after sunset. It's Venus in a crescent phase. About 40 million kilometers away and about 2 percent illuminated by sunlight...

APOD: 2025 February 25 Б M41: The Little Beehive Star Cluster
25.02.2025

Why are there so many bright blue stars? Stars are usually born in clusters, and the brightest and most massive of these stars typically glow blue. Less-bright, non-blue stars like our Sun surely also exist in this M41 star cluster but are harder to see. A few bright orange-appearing red giant stars are visible.

M27: The Dumbbell Nebula
6.03.2001

The first hint of what will become of our Sun was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of "annoying" diffuse objects not to be confused with "interesting" comets.

NGC 2346: A Butterfly-Shaped Planetary Nebula
28.10.2001

It may look like a butterfly, but it's bigger than our Solar System. NGC 2346 is a planetary nebula made of gas and dust that has evolved into a familiar shape. At the heart of the bipolar planetary nebula is a pair of close stars orbiting each other once every sixteen days.