APOD: 2025 October 20 Б Finding Comet Lemmon
20.10.2025

Tonight, if you can see the stars of the Big Dipper, then you can find comet Lemmon in your evening sky. After sunset, look for the faint but extended comet above your northwestern horizon -- but below the handle of the famous celestial kitchen utensil of the north.

Arp 286: Trio in Virgo
10.06.2022

This colorful telescopic field of view features a trio of interacting galaxies almost 90 million light-years away, toward the constellation Virgo. On the right two spiky, foreground Milky Way stars echo the extragalactic hues, a reminder that stars in our own galaxy are like those in distant island universes.

Antlia: A New Galactic Neighbor
23.04.1997

Meet Antlia, a newly discovered neighbor of our Milky Way Galaxy. Announced just last week, this faint member of our Local Group of Galaxies has only about one million stars. It is late in being noticed because it is so hard to see against a bright sky.

A Conjunction of Comets
23.09.2017

A conjunction of comets is captured in this pretty star field from the morning of September 17. Discovered in July by a robotic sky survey searching for supernovae, comet C/2017 O1 ASASSN is at the lower left. The visible greenish glow of its coma is produced by the fluorescence of diatomic carbon molecules in sunlight.

Moons and Bright Mars
1.08.2003

In this serene view, the moons of Earth along with the bright planet Mars shine above the city of Turku near the southwestern tip of Finland. Of course Earth's large natural satellite, the Moon, at a distance of 400,000 kilometers, is by far the brightest object in this sky.

Elliptical Galaxy M87
16.06.2004

Elliptical galaxy M87 is a type of galaxy that looks much different than our own Milky Way Galaxy. Even for an elliptical galaxy, though, M87 is peculiar. M87 is much bigger than an average...

NGC 2683: Edge On Spiral Galaxy
5.02.2014

Does spiral galaxy NGC 2683 have a bar across its center? Being so nearly like our own barred Milky Way Galaxy, one might guess it has. Being so nearly edge-on, however, it is hard to tell.

Teimareh Petroglyphs and Star Trails
12.07.2012

Engraved in rock, these ancient petroglyphs are abundant in the Teimareh valley, located in the Zagros Mountains of central Iran. They likely tell a tale of hunters and animals found in the middle eastern valley 6,000 years ago or more, etched by artists in a prehistoric age.

APOD: 2023 December 27 Б Rainbow Aurora over Icelandic Waterfall
27.12.2023

Yes, but can your aurora do this? First, yes, auroras can look like rainbows even though they are completely different phenomena. Auroras are caused by Sun-created particles being channeled into Earth's atmosphere by Earth's magnetic field, and create colors by exciting atoms at different heights.

The Supernova and Cepheids of Spiral Galaxy UGC 9391
6.06.2016

What can this galaxy tell us about the expansion rate of the universe? Perhaps a lot because UGC 9391, featured, not only contains Cepheid variable stars (red circles) but also a recent Type Ia supernova (blue X).