Sunrise Analemma (with a little extra)
20.09.2012

An analemma is that figure-8 curve that you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. In this case, 17 individual images...

APOD: 2024 November 6 Б Comet Tsuchinshan Atlas over the Dolomites
5.11.2024

Comet Tsuchinshan-Atlas is now headed back to the outer Solar System. The massive dusty snowball put on quite a show during its trip near the Sun, resulting in many impressive pictures from planet Earth during October. The featured image was taken in mid-October and shows a defining visual feature of the comet -- its impressive anti-tail.

APOD: 2025 November 3 Б A Double Helix Lunar Eclipse
2.11.2025

The image was timed to capture a total lunar eclipse -- but it came with quite a twist. First, the eclipse: the fully Earth-shadowed Moon is visible as the orange orb near the top.

Discovery Spring
19.03.2001

Welcome to the equinox! Moving northward in Earth's sky, today the Sun crosses the celestial equator at 13:31 Universal Time bringing Spring to the north and Fall to the south. The change...

Outbound from Mercury
16.07.2002

After just passing Mercury, the robot spacecraft Mariner 10 looked back. The above picture is what it saw. Mercury, the closest planet to the Sun, is heavily cratered much like Earth's Moon.

Anticrepuscular Rays over Florida
17.03.2020

What's happening behind those clouds? Although the scene may appear somehow supernatural, nothing more unusual is occurring than a Sun setting on the other side of the sky. Pictured here are anticrepuscular rays. To understand them, start by picturing common crepuscular rays that are seen any time that sunlight pours though scattered clouds.

APOD: 2024 March 4 Б Light Pillars Over Inner Mongolia
3.03.2024

What's happening across that field? Pictured here are not auroras but nearby light pillars, a phenomenon typically much closer. In most places on Earth, a lucky viewer can see a Sun pillar, a column of light appearing to extend up from the Sun caused by flat fluttering ice-crystals reflecting sunlight from the upper atmosphere.

The Local Fluff
29.08.2010

The stars are not alone. In the disk of our Milky Way Galaxy about 10 percent of visible matter is in the form of gas, called the interstellar medium (ISM). The ISM is not uniform, and shows patchiness even near our Sun.

Mercury Spotting
27.05.2012

Can you spot the planet? The diminutive disk of Mercury, the solar system's innermost planet, spent about five hours crossing in front of the enormous solar disk in 2003, as viewed from the general vicinity of planet Earth.

Anticrepuscular Rays Over Colorado
27.11.2010

What's happening over the horizon? Although the scene may appear somehow supernatural, nothing more unusual is occurring than a setting Sun and some well placed clouds. Pictured above are anticrepuscular rays. To understand them, start by picturing common crepuscular rays that are seen any time that sunlight pours though scattered clouds.