The W in Cassiopeia
18.03.2016

A familiar, zigzag, W pattern in northern constellation Cassiopeia is traced by five bright stars in this colorful and broad mosaic. Stretching about 15 degrees across rich starfields, the celestial scene includes dark clouds, bright nebulae, and star clusters along the Milky Way. In yellow-orange hues Cassiopeia's alpha star Shedar is a standout though.

The Long Gas Tail of Spiral Galaxy D100
28.01.2019

Why is there long red streak attached to this galaxy? The streak is made mostly of glowing hydrogen that has been systematically stripped away as the galaxy moved through the ambient hot gas in a cluster of galaxies. Specifically, the galaxy is spiral galaxy D100, and cluster is the Coma Cluster of galaxies.

M33: The Triangulum Galaxy
3.11.2022

The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way.

APOD: 2025 June 3 Б Rainbow Airglow over the Azores
3.06.2025

Why would the sky glow like a giant repeating rainbow? Airglow. Now, air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere.

From California to the Pleiades
22.11.2013

An astronomical trip from the California Nebula to the Pleiades star cluster would cover just 12 degrees across planet Earth's night sky. That's equivalent to the angular extent of 25 Full Moons, as your telescope sweeps over the borders of the constellations Perseus and Taurus.

The Sky from Mauna Kea
11.05.2015

What if you could stand at the top of a volcano and peer out across the universe? It the timing is right, you might see an amazing panorama like the one featured here.

Charon: Moon of Pluto
6.07.2018

A darkened and mysterious north polar region known to some as Mordor Macula caps this premier high-resolution view. The portrait of Charon, Pluto's largest moon, was captured by New Horizons near the spacecraft's closest approach on July 14, 2015.

Sunspot Stack
19.04.2001

Welcome to multiwavelength astronomy! From top to bottom, these stacked panels show the largest sunspot group in a decade in visible, extreme ultraviolet, and x-ray light. All were taken on March 29, around...

Comet McNaught Passes NGC 1245
17.06.2010

Of the many comets named for discoverer Robert McNaught, the one cataloged as C/2009 R1 is gracing dawn skies for northern hemisphere observers this month. Seen here on June 13th from southern New Mexico, this Comet McNaught's long ion tail sweeps across the telescopic field of view (a negative image is inset).

M57: The Ring Nebula
20.04.2012

Except for the rings of Saturn, the Ring Nebula (M57) is probably the most famous celestial band. Its classic appearance is understood to be due to perspective - our view from planet Earth looks down the center of a roughly barrel-shaped cloud of glowing gas.