Mercurys Sodium Tail
3.05.2022

That's no comet. Below the Pleiades star cluster is actually a planet: Mercury. Long exposures of our Solar System's innermost planet may reveal something unexpected: a tail. Mercury's thin atmosphere contains small amounts of sodium that glow when excited by light from the Sun.

Two Views of Earth
23.07.2013

In a cross-Solar System interplanetary first, our Earth was photographed during the same day from both Mercury and Saturn. Pictured on the left, Earth is the pale blue dot just below the rings of Saturn, as captured by the robotic Cassini spacecraft now the gas giant.

APOD: 2025 November 25 Б Comet Lemmon and the Milky Way
25.11.2025

What did Comet Lemmon look like when it was at its best? One example is pictured here, featuring three celestial spectacles all at different distances. The closest spectacle is the snowcapped Meili Mountains, part of the Himalayas in China.

Look West for a NEAT Comet
7.05.2004

On May 5th, while scanning western skies after sunset, astronomer Jimmy Westlake was glad to spot a visitor from the outer solar system, Comet NEAT, with his own eyes. Taken with a normal lens...

Tails of Comet Garradd
20.10.2011

A good target for binoculars and small telescopes, Comet Garradd (C/2009 P1) now shines in planet Earth's evening skies, a steady performer but just below naked-eye visibility. Telescopic images like this composite from...

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.

Comet ATLAS Breaks Up
16.04.2020

Cruising through the inner solar system, Comet ATLAS C2019/Y4 has apparently fragmented. Multiple separate condensations within its diffuse coma are visible in this telescopic close-up from April 12, composed of frames tracking the comet's motion against trailing background stars.

APOD: 2023 May 24 Б Observatory Aligned with Moon Occulting Jupiter
24.05.2023

Sometimes we witness the Moon moving directly in front of -- called occulting -- one of the planets in our Solar System. Earlier this month that planet was Jupiter. Captured here was the moment when Jupiter re-appeared from behind the surface of our Moon.

Phobos: Moon over Mars
22.03.2024

A tiny moon with a scary name, Phobos emerges from behind the Red Planet in this timelapse sequence from the Earth-orbiting Hubble Space Telescope. Over 22 minutes the 13 separate exposures were captured near the 2016 closest approach of Mars to planet Earth. Martians have to look to the west to watch Phobos rise, though.

APOD: 2026 February 1 Б Galle: Happy Face Crater on Mars
1.02.2026

Mars has put on a happy face. The Martian crater Galle is famous because it has internal markings that make it look like a face that is both smiling and winking. These markings were originally discovered in the 1970s in pictures taken by the Viking Orbiter.