The Umbra of Earth
15.12.2011

The dark, inner shadow of planet Earth is called the umbra. Shaped like a cone extending into space, it has a circular cross section most easily seen during a lunar eclipse. For example, last Saturday the Full Moon slid across the southern half of Earth's umbral shadow, entertaining moonwatchers around much of the planet.

The Crown of the Sun
7.04.2006

During a total solar eclipse, the Sun's extensive outer atmosphere or corona is an awesome and inspirational sight. The subtle shades and shimmering features of the corona that engage the eye span a brightness range of over 10,000 to 1, making them notoriously difficult to capture in a single picture.

Earth at Night
5.10.2008

This is what the Earth looks like at night. Can you find your favorite country or city? Surprisingly, city lights make this task quite possible. Human-made lights highlight particularly developed or populated areas of the Earth's surface, including the seaboards of Europe, the eastern United States, and Japan.

Moon AND Sun
7.09.2001

Today's composite image was made from 22 separate pictures of the Moon and Sun all taken from Chisamba, Zambia during the total phase of the 2001 June 21 solar eclipse. The multiple exposures...

The Tulip in the Swan
20.10.2016

Framing a bright emission region this telescopic view looks out along the plane of our Milky Way Galaxy toward the nebula rich constellation Cygnus the Swan. Popularly called the Tulip Nebula, the glowing cloud of interstellar gas and dust is also found in the 1959 catalog by astronomer Stewart Sharpless as Sh2-101.

A Zodiacal Sky over Horseshoe Bend
22.05.2017

What's causing the unusual ray of white light extending upward from the central horizon? Dust orbiting the Sun. At certain times of the year, a band of sun-reflecting dust from the inner Solar System rises prominently before sunrise and is called zodiacal light.

Perseids from Perseus
10.08.2020

Where are all these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Perseus. That is why the meteor shower that peaks tomorrow night is known as the Perseids -- the meteors all appear to came from a radiant toward Perseus.

APOD: 2023 September 11 Б Beautiful Comet Nishimura
11.09.2023

This scene would be beautiful even without the comet. By itself, the sunrise sky is an elegant deep blue on high, with faint white stars peeking through, while near the horizon is a pleasing tan.

The Solar Corona Unwrapped
5.04.2024

Changes in the alluring solar corona are detailed in this creative composite image mapping the dynamic outer atmosphere of the Sun during two separate total solar eclipses. Unwrapped from the complete circle...

APOD: 2024 April 28 Б Rings Around the Ring Nebula
28.04.2024

The Ring Nebula (M57) is more complicated than it appears through a small telescope. The easily visible central ring is about one light-year across, but this remarkably deep exposure - a collaborative effort combining data from three different large telescopes - explores the looping filaments of glowing gas extending much farther from the nebula's central star.