APOD: 2024 July 9 Б Noctilucent Clouds over Florida
9.07.2024

These clouds are doubly unusual. First, they are rare noctilucent clouds, meaning that they are visible at night -- but only just before sunrise or just after sunset. Second, the source of these noctilucent clouds is actually known.

APOD: 2023 January 3 Б Kembles Cascade of Stars
3.01.2023

This line of stars is real. A little too faint to see with the unaided eye, KembleБs Cascade of stars inspires awe when seen with binoculars. Like the Big Dipper though, KembleБs Cascade is an asterism, not a constellation. The asterism is visible in the northern sky toward the long-necked constellation of the Giraffe (Camelopardalis).

APOD: 2023 April 18 Б Map of Total Solar Eclipse Path in 2024 April
18.04.2023

Would you like to see a total eclipse of the Sun? If so, do any friends or relatives live near the path of next April's eclipse? If yes again, then you might want to arrange a well-timed visit.

APOD: 2024 December 18 Б NGC 660: Polar Ring Galaxy
18.12.2024

What kind of strange galaxy is this? This rare structure is known as a polar ring galaxy, and it seems to have two different rings of stars. In this galaxy, NGC 660, one ring...

APOD: 2025 July 18 Б ISS Meets Saturn
18.07.2025

This month, bright planet Saturn rises in evening skies, its rings oriented nearly edge-on when viewed from planet Earth. And in the early morning hours on July 6, it posed very briefly with the International Space Station when viewed from a location in Federal Way, Washington, USA.

APOD: 2025 August 30 Б A Two Percent Moon
30.08.2025

A young crescent moon can be hard to see. That's because when the Moon shows it's crescent phase (young or old) it can never be far from the Sun in planet Earth's sky.

APOD: 2023 March 13 Б Rainbow Tree
13.03.2023

What lies at the end of a rainbow? Something different for everyone. For the photographer taking this picture, for example, one end of the rainbow ended at a tree. Others nearby, though, would likely see the rainbow end somewhere else. The reason is because a rainbow's position depends on the observer.

APOD: 2024 December 2 Б NGC 300: A Galaxy of Stars
2.12.2024

This galaxy is unusual for how many stars it seems that you can see. Stars are so abundantly evident in this deep exposure of the spiral galaxy NGC 300 because so many of these stars are bright blue and grouped into resolvable bright star clusters.

APOD: 2025 July 6 Б The Spiral North Pole of Mars
6.07.2025

Why is there a spiral around the North Pole of Mars? Each winter this pole develops a new outer layer about one meter thick composed of carbon dioxide frozen out of the thin Martian atmosphere. This fresh layer is deposited on a water-ice layer that exists year round.

APOD: 2023 October 25 Б Gone in 60 Seconds: A Green Flash Sunset
25.10.2023

In 60 seconds, this setting Sun will turn green. Actually, the top of the Sun already appears not only green, but wavey -- along with all of its edges. The Sun itself is unchanged -- both effects are caused by looking along hot and cold layers in Earth's atmosphere.