The Decade that Defined Star System
28.12.1999

As the 1990s began, the only planetary star system known was our own Solar System. The first extra-solar star system was discovered orbiting a pulsar in 1991. Slight changes in the precise arrival times of the pulses from the central small dense neutron star gave evidence of orbiting planets.

Perseid Meteors over Turkey
31.07.2017

The Perseid Meteor Shower, usually the best meteor shower of the year, will peak late next week. A person watching a clear sky from a dark location might see a bright meteor every minute.

Lunar Dust and Duct Tape
27.03.2025

Why is the Moon so dusty? On Earth, rocks are weathered by wind and water, creating soil and sand. On the Moon, eons of constant micrometeorite bombardment have blasted away at the rocky surface creating a layer of powdery lunar soil or regolith.

Vega
23.08.1998

Vega is a bright blue star 25 light years away. Vega is the brightest star in the Summer Triangle, a group of stars easily visible summer evenings in the northern hemisphere. The name Vega...

APOD: 2020 August 15 Б Mars at the Moons Edge
14.08.2020

Does the Moon ever block out Mars? Yes, the Moon occasionally moves in front of all of the Solar System's planets. Just this past Sunday, as visible from some locations in South America, a waning gibbous Moon eclipsed Mars.

Jupiter by Moonlight
2.11.2023

That bright beacon you've seen rising in the east just after sunset is Jupiter. Climbing high in midnight skies, our Solar System's ruling gas giant was at its 2023 opposition, opposite the Sun in planet Earth's sky, on November 2.

The North Pole of Venus
14.05.2003

If you could look down on the North Pole of Venus what would you see? The Magellan probe that orbited Venus from 1990 to 1994 was able to peer through the thick Venusian clouds and build up the above image by emitting and re-detecting cloud-penetrating radar.

A Twilight Occultation
9.12.2010

A thin, one day old crescent Moon hugged the western horizon after sunset on Monday, December 6. The Moon also occulted or passed in front of Mars. But only some well-placed skygazers along a band through North America were able to catch this lunar occultation's final act in fading twilight.

Lunar Occultation of Mercury
27.02.2026

Fans of the western sky after sunset have lately enjoyed this month's remarkable array of bright planets. Witnessed from some locations, on February 18 planet Mercury even appeared to slide behind the Moon, an event known as a lunar occultation.

A Glimpse of CLIMSO
25.11.2011

A tantalizing glimpse inside this dome was captured after sunset at the mountain top Pic Du Midi Observatory in the French Pyrenees. But while most are just beginning their work at sunset, this observatory's day was done.