The Veins of Heaven
25.07.2019

Transfusing sunlight through a still dark sky, this exceptional display of noctilucent clouds was captured earlier this month, reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden. From the edge of space...

A Double Star Cluster in Perseus
21.11.2022

Few star clusters this close to each other. Visible to the unaided eye from dark sky areas, it was cataloged in 130 BC by Greek astronomer Hipparchus. Some 7,000 light-years away, this pair...

APOD: 2024 January 22 Б Shadows of Mountain and Moon
21.01.2024

Can the Moon and a mountain really cast similar shadows? Yes, but the division between light and dark does not have to be aligned. Pictured, a quarter moon was captured above the mountain Grivola in Italy in early October of 2022.

APOD: 2025 August 7 Б The Double Cluster in Perseus
6.08.2025

This stunning starfield spans about three full moons (1.5 degrees) across the heroic northern constellation of Perseus. It holds the famous pair of open star clusters, h and Chi Persei. Also cataloged...

A 2000 Leonid Through Orion
19.11.2000

The Leonid Meteor Shower this year could be described as good but not great. During November 17 and 18 the Earth crossed through several streams of sand-sized grit left orbiting the Sun by Comet Tempel-Tuttle. Several distinct peaks in meteor activity were reported, with

Antares and Rho Ophiuchi
22.09.1997

Why is the sky near Antares and Rho Ophiuchi so colorful? The colors result from a mixture of objects and processes. Fine dust illuminated from the front by starlight produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae. Backlit dust clouds block starlight and so appear dark.

The Long Shadow of the Moon
26.11.2003

The long shadow of the Moon fell across the continent of Antarctica on November 23rd, during the second total solar eclipse of 2003. In this view from orbit, based on data from the MODIS instrument on board the Earth observing Aqua satellite, the Moon's shadow stretches for almost 500 kilometers.

Jupiter Swallows Comet Shoemaker Levy 9
4.08.1998

What happens when a comet encounters a planet? If the planet has a rocky surface, a huge impact feature will form. A giant planet like Jupiter, however, is mostly gas. When Comet Shoemaker-Levy 9 struck Jupiter in 1994, each piece was swallowed into the vast Jovian atmosphere.

Nozomi: Earth and Moon
4.09.1998

Japan launched its first mission to orbit Mars, Nozomi (Hope), on July 3rd from the Kagoshima Space Center on the island of Kyushu. Nozomi's goal is to explore the Martian atmosphere and magnetic field as well as regions of the planet's surface and moons.

Spiral Sunspot
3.02.1999

Spiral galaxies abound in the universe, but spiral sunspots are definitely an unusual twist. This distinctive spiral-shaped sunspot caught the attention of National Solar Observatory astronomers and was photographed on February 19, 1982 with the Vacuum Solar Telescope on Kitt Peak.