APOD: 2023 December 11 Б Solar Minimum versus Solar Maximum
10.12.2023

The surface of our Sun is constantly changing. Some years it is quiet, showing relatively few sunspots and active regions. Other years it is churning, showing many sunspots and throwing frequent Coronal Mass Ejections (CMEs) and flares.

Andromeda on the Rocks
27.09.2013

How far can you see? The Andromeda Galaxy 2.5 million light years away is the most distant object easily seen by the unaided eye. Other apparent denizens of the night sky, stars, clusters...

APOD: 2025 September 26 Б A SWAN an ATLAS and Mars
25.09.2025

A new visitor to the inner Solar System, comet C/2025 R2 (SWAN) sports a long ion tail extending diagonally across this almost 7 degree wide telescopic field of view recorded on September 21.

Jupiter, Saturn and Messier 45
21.03.2001

Brilliant Venus falls out of the evening sky as March ends, but Jupiter and Saturn remain well up above the western horizon. Jupiter blazes forth above and to the left of a slightly fainter Saturn in this telephoto picture taken on January 19th.

Star Trails for a Red Planet
29.11.2019

Does Mars have a north star? In long exposures of Earth's night sky, star trails make concentric arcs around the north celestial pole, the direction of our fair planet's axis of rotation. Bright star Polaris is presently the Earth's North Star, close on the sky to Earth's north celestial pole.

Phases of the Moon
9.03.2018

Look at the Moon every night and its visible sunlit portion gradually changes. In phases progressing from New Moon to Full Moon to New Moon again, a lunar cycle or lunation is completed in about 29.5 days.

A Dark Sky Over Death Valley
13.07.2008

This eerie glow over Death Valley is in danger. Scrolling right will show a spectacular view from one of the darkest places left in the continental USA: Death Valley, California. The above 360-degree full-sky panorama is a composite of 30 images taken two years ago in Racetrack Playa.

APOD: 2025 February 9 Б Milky Way over the Australian Pinnacles
8.02.2025

What strange world is this? Earth. In the foreground of the featured image are the Pinnacles, unusual rock spires in Nambung National Park in Western Australia. Made of ancient sea shells (limestone), how these human-sized picturesque spires formed remains unknown.

Aura Launch
22.07.2004

In this alluring time exposure, star trails arc across the night sky above Monterey Bay and the lights of Santa Cruz, California, USA. But since the exposure began around 3:01am PDT on July 15 it also records the long trail of a Delta II rocket lofting NASA's Aura spacecraft into Earth orbit.

Geminids over Kit Peak
15.12.2010

Two large telescope domes stand in the foreground of this night sky view from Kitt Peak National Observatory, near Tucson, Arizona, USA. The dramatic scene was recorded early Tuesday morning, near the peak of December's Geminid Meteor Shower.