Comet Ikeya Zhang Brightens
7.03.2002

In the last week, Comet Ikeya-Zhang has become bright enough to be just visible to the unaided eye. Based on its present activity, observers are optimistic that Ikeya-Zhang will become substantially brighter. This composite...

Two Million Galaxies
7.10.2007

Our universe is filled with galaxies. Galaxies -- huge conglomerations of stars, gas, dust -- and mysterious dark matter are the basic building blocks of the large-scale universe. Although distant galaxies move away from each other...

A Picturesque Venus Transit
3.06.2012

The rare transit of Venus across the face of the Sun in 2004 was one of the better-photographed events in sky history. Both scientific and artistic images flooded in from the areas that could see the transit: Europe and much of Asia, Africa, and North America.

Milky Way Over Crater Lake with Airglow
19.06.2013

How many different astronomical phenomena have come together to create the above vista? Several. First, in the foreground, is Crater Lake -- a caldera created by volcanism on planet Earth about 7,700 years ago. Next, inside the lake, is water.

When Z is for Mars
15.04.2023

A composite of images captured about a week apart from mid August 2022 through late March 2023, this series traces the retrograde motion of ruddy-colored Mars. Progressing from lower right to upper left Mars...

APOD: 2023 December 10 Б Big Dipper over Pyramid Mountain
10.12.2023

When did you first learn to identify this group of stars? Although they are familiar to many people around the world, different cultures have associated this asterism with different icons and folklore. Known...

Panoramic Eclipse Composite with Star Trails
30.08.2017

What was happening in the sky during last week's total solar eclipse? This featured little-planet, all-sky, double time-lapse, digitally-fused composite captured celestial action during both night and day from a single location.

Equinox: The Sun from Solstice to Solstice
23.09.2019

Today is an equinox, a date when day and night are equal. Tomorrow, and every day until the next equinox, the night will be longer than the day in Earth's northern hemisphere, and the day will be longer than the night in Earth's southern hemisphere.

Streak and Plume from SpaceX Crew2 Launch
24.04.2021

What's happening in the sky? The pre-dawn sky first seemed relatively serene yesterday morning over Indian Harbor Beach in Florida, USA. But then it lit up with a rocket launch. Just to the north, NASA's SpaceX Crew-2 Mission blasted into space aboard a powerful Falcon 9 rocket.

Comet Halley vs Comet SWAN
14.05.2020

The pre-dawn hours of May 3rd were moonless as grains of cosmic dust streaked through southern skies above Reunion Island. Swept up as planet Earth plowed through dusty debris streams left behind periodic Comet 1/P Halley, the annual meteor shower is known as the Eta Aquarids.