Moon Pi and Mountain Shadow
13.03.2024

What phase of the Moon is 3.14 radians from the Sun? The Full Moon, of course. Even though the Moon might look full for several days, the Moon is truly at its full phase when it is Pi radians (aka 180 degrees) from the Sun in ecliptic longitude.

Comet Hyakutake and a Tree
10.04.1996

Comet Hyakutake is still visible as it continues its orbit around the Sun. The comet will brighten again in late April and early May. The above fascinating picture was taken with a three minute exposure. In the middle of the exposure, the photographer cleverly set off a flash, momentarily illuminating the foreground tree.

Orange Sun Oozing
6.11.2011

The Sun's surface keeps changing. The above movie shows how the Sun's surface oozes during a single hour. The Sun's photosphere has thousands of bumps called granules and usually a few dark depressions called sunspots.

Moon Pi and Mountain Shadow
13.03.2025

What phase of the Moon is 3.14 radians from the Sun? The Full Moon, of course. Even though the Moon might look full for several days, the Moon is truly at its full phase when it is Pi radians (aka 180 degrees) from the Sun in ecliptic longitude.

The Light of Stars
8.05.2012

What's moving? Time lapse videos of the sky can be quite spectacular when they last long enough for stars, planets, aurora, and clouds to appear to move in just a few seconds. Pictured...

NGC 6888: The Crescent Nebula
15.09.2009

NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. This beautiful portrait of the nebula is from the Isaac Newton Telescope at Roque de los Muchachos Observatory in the Canary Islands.

Halo of the Cat's Eye
31.10.2003

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...

The Sharpest View of the Sun
13.11.2002

This stunning image shows remarkable and mysterious details near the dark central region of a planet-sized sunspot in one of the sharpest views ever of the surface of the Sun. Just released, the picture was made using the Swedish Solar Telescope now in its first year of operation on the Canary Island of La Palma.

Cherenkov Telescope at Sunset
17.10.2018

On October 10, a new telescope reflected the light of the setting Sun. With dark horizon above and sunset colors below, its segmented mirror inverts an image of the beautiful evening sky in this snapshot from the Roque del Los Muchachos Observatory on the Canary Island of La Palma.

The Milky Way Over Tenerife
5.04.2011

Have you ever seen the band of our Milky Way Galaxy? Chances are you have never seen it like this -- nor could you. In a clear sky from a dark location at the right time, a faint band of light is visible across the sky. This band is the disk of our spiral galaxy.