The Umbra of Earth
25.01.2019

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...

A Violet Moon
31.07.1996

Checking out the Galileo spacecraft's cameras during its December 1992 flyby of Earth's Moon, controllers took this dramatically illuminated picture through a violet filter. The view looks down on the Moon...

Highlights of the North Spring Sky
12.03.2019

What can you see in the night sky this season? The featured graphic gives a few highlights for Earth's northern hemisphere. Viewed as a clock face centered at the bottom, early (northern) spring sky events fan out toward the left, while late spring events are projected toward the right.

Celestial Alignment over Sicilian Shore
3.03.2019

This was a sunrise to remember. About a month ago, just before the dawn of the Sun, an impressive alignment of celestial objects was on display to the east. Pictured, brightest and closest to the horizon, is the Moon.

Total Solar Lunar Eclipse
8.02.2018

This digitally processed and composited picture creatively compares two famous eclipses in one; the total lunar eclipse (left) of January 31, and the total solar eclipse of August 21, 2017. The Moon appears near mid-totality in both the back-to-back total eclipses.

APOD: 2025 March 4 Б A Quadruple Alignment over Italy
3.03.2025

Why does this Moon look so unusual? A key reason is its vivid red color. The color is caused by the deflection of blue light by Earth's atmosphere -- the same reason that the daytime sky appears blue. The Moon also appears unusually distorted.

Stars in a Dusty Sky
28.09.2012

Bright star Markab anchors this dusty skyscape. At the top right corner of the frame, Markab itself marks a corner of an asterism known as the Great Square, found within the boundaries of the constellation Pegasus, the flying horse.

The Geminid
15.12.2022

Returning from beyond the Moon, on December 11 the Orion spacecraft entered Earth's atmosphere at almost 11 kilometers per second. That's half the speed of the grain of dust that created this long fireball meteor when it entered the atmosphere on December 13, near the peak of the annual Geminid meteor shower.

Eclipsed Moon in the Morning
24.12.2011

December's lunar eclipse graced early morning skies over the Rocky Mountains in Colorado, USA. There, this wintry scene finds the Moon in a cold blue twilight sky near the western horizon, above the snowy North American Continental Divide.

NGC 6960: The Witch's Broom Nebula
31.12.2002

Ten thousand years ago, before the dawn of recorded human history, a new light must suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was an exploding star and record the colorful expanding cloud as the Veil Nebula.