A Meteor Shower Fireball Movie
12.08.2005

Go outside tonight and see a celestial light show -- the later the better. Tonight is the peak of the month-long Perseid Meteor Shower. Although visible every year at this time, the Perseids are expected to appear particularly active this year due to the relative absence of glare from the Moon during the peak.

Halo of the Cats Eye
9.05.2010

The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this stunning false-color picture, processed...

Halo of the Cat's Eye
1.11.2003

The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this stunning false-color picture, processed...

Madagascar Totality
26.07.2001

When the Moon's shadow reached out and touched Earth's southern hemisphere on 2001 June 21, the first total solar eclipse of the 21st century began. Starting in the Atlantic, the dark, central...

APOD: 2023 August 15 Б A Triply Glowing Night Sky over Iceland
15.08.2023

The Sun is not the quiet place it seems. It expels an unsteady stream of energetic electrons and protons known as the solar wind. These charged particles deform the Earth's magnetosphere, change paths...

A Seemingly Square Sun
26.05.1998

Isn't the Sun round? Yes, but in the above picture, the Earth's atmosphere makes it appear almost square. Here a layer of air near the Earth was so warm it acted like a giant lens, creating increasingly distorted paths for sunlight to reach the camera.

A Solar Filament Erupts
17.09.2012

What's happened to our Sun? Nothing very unusual -- it just threw a filament. At the end of last month, a long standing solar filament suddenly erupted into space producing an energetic Coronal Mass Ejection (CME).

X Ray Moon
2.09.2000

This x-ray image of the Moon was made by the orbiting ROSAT (Röntgensatellit) Observatory in 1990. In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray moon, the darker half of the moon, and the x-ray sky background.

A Tail of Two Hemispheres
1.02.2007

By January 19/20 Comet McNaught's magnificent dust tail stretched for about 150 million kilometers (~1 AU), requiring images from both southern and northern hemispheres of planet Earth to take it all in.

APOD: 2023 September 9 Б Comet Nishimura Grows
9.09.2023

Comet Nishimura is growing. More precisely, the tails C/2023 P1 (Nishimura) are growing as it nears the Sun. Discovered only last month, the comet is already near naked eye brightness as it now moves inside the Earth's orbit.