The Pleiades Star Cluster
3.09.1996

It is the most famous star cluster on the sky. The Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and most easily visible open clusters on the sky.

M6: The Butterfly Cluster
6.01.1999

To some, the outline of the open cluster of stars M6 resembles a butterfly. M6, also known as NGC 6405, spans about 20 light-years and lies about 2,000 light years distant.

Zodiacal Light and the False Dawn
15.09.2002

An unusual triangle of light will be particularly bright near the eastern horizon before sunrise during the next two months for observers in Earth's northern hemisphere. Once considered a false dawn, this triangle of light is actually Zodiacal Light, light reflected from interplanetary dust particles.

Pleiades Deep Field
21.09.2011

Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it like this: all dusty. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city.

GW151226: A Second Confirmed Source of Gravitational Radiation
15.06.2016

A new sky is becoming visible. When you look up, you see the sky as it appears in light -- electromagnetic radiation. But just over the past year, humanity has begun to see our once-familiar sky as it appears in a different type of radiation -- gravitational radiation.

Eclipse on the Beach
30.07.2010

As the New Moon's shadow slid across the southern Pacific on July 11, people gathered along the white, sandy Anakena Beach on the north side of Easter Island to watch a total solar eclipse. The experience was captured in this tantalizing composite image, constructed from a sequence of 50 consecutive exposures.

Star Trails Above Table Mountain
25.06.2015

Stars trail above and urban lights sprawl below in this moonlit nightscape from Cape Town, South Africa, planet Earth. The looming form of Table Mountain almost seems to hold terrestrial lights at bay while the stars circle the planet's South Celestial Pole.

X Ray Moon
14.09.2002

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.

Atmospheric Ring of Venus
8.06.2020

Why is Venus surrounded by a bright ring? Sometimes called a ring of fire, this rare ring is caused by the Sun's light being visible all around an object. Usually seen around...

APOD: 2023 July 4 Б Aurora over Icelandic Waterfall
4.07.2023

It seemed like the sky exploded. The original idea was to photograph an aurora over a waterfall. After waiting for hours under opaque clouds, though, hope was running out. Others left. Then, unexpectedly, the clouds moved away.