USNO A2.0 Catalog: A Digital Sky
26.04.1999

Here lie 526,230,881 of the brightest stars known. The US Naval Observatory has deployed their monster Precision Measuring Machine to digitize photographic plates covering the whole sky and creating the above map. Yellow corresponds to 150,000 stars per square degree, while dark blue corresponds to only 500 stars per square degree.

Sundogs over the VLA
23.08.1999

What if you woke up one morning and saw more than one Sun in the sky? Most probably, you would be seeing sundogs, extra-images of the Sun created by falling ice-crystals in the Earth's atmosphere. As water freezes in the atmosphere, small, flat, six-sided, ice crystals might be formed.

A Spectre in the Eastern Veil
1.11.2008

Menacing flying forms and garish colors are a mark of the Halloween season. They also stand out in this cosmic close-up of the eastern Veil Nebula. The Veil Nebula itself is a large supernova remnant, the expanding debris cloud from the death explosion of a massive star.

APOD: 2015 July 12 New Horizons Launch to Pluto
12.07.2015

Destination: Pluto. The New Horizons spacecraft roared off its launch pad at Cape Canaveral in Florida, USA in 2006 toward adventures in the distant Solar System. The craft is the fastest spaceships ever launched by humans, having passed the Moon only nine hours after launch, and Jupiter only a year later.

GW Orionis: A Star System with Titled Rings
29.09.2020

Triple star system GW Orionis appears to demonstrate that planets can form and orbit in multiple planes. In contrast, all the planets and moons in our Solar System orbit in nearly the same plane. The picturesque system has three prominent stars, a warped disk, and inner tilted rings of gas and grit.

NGC 6995: The Bat Nebula
27.10.2021

Do you see the bat? It haunts this cosmic close-up of the eastern Veil Nebula. The Veil Nebula itself is a large supernova remnant, the expanding debris cloud from the death explosion of a massive star.

Geminids and the Mittens
25.12.2022

Asteroid 3200 Phaethon's annual gift to planet Earth always arrives in December. Otherwise known as the Geminid meteor shower, the source of the meteroid stream is dust shed along the orbit of the mysterious asteroid.

APOD: 2023 February 7 Б A Comet and Two Dippers
7.02.2023

Can you still see the comet? Yes. Even as C/2022 E3 (ZTF) fades, there is still time to see it if you know where and when to look. Geometrically, Comet ZTF has passed its closest to both the Sun and the Earth and is now headed back to the outer Solar System.

Pwyll: Icy Crater of Europa
13.04.2002

The impact crater Pwyll (a name from Celtic Mythology) is thought to represent one of the youngest features on the surface of Jupiter's moon Europa. A combination of color and high resolution black...

M55: Globular Star Cluster
18.09.2004

The fifty-fifth entry in Charles Messier's catalog, M55 is a large and lovely globular cluster of around 100,000 stars. Only 20,000 light-years away in the constellation Sagittarius, M55 appears to earth-bound observers to be nearly 2/3 the size of the full moon.