The Anthe Arc around Saturn
10.09.2008

What created this unusual partial ring around Saturn? Discovered last year, the arc was captured in clear detail only two months ago by the Saturn-orbiting Cassini spacecraft. Since the arc occupies the same orbit...

APOD: 2023 April 26 Б The Moon through the Arc de Triomphe
26.04.2023

Was this a lucky shot? Although many amazing photographs are taken by someone who just happenedбto be in the right place at the right time, this image took skill and careful planning. First...

APOD: 2025 August 4 Б Blue Arcs Toward Andromeda
4.08.2025

What are these gigantic blue arcs near the Andromeda Galaxy (M31)? Discovered in 2022 by amateur astronomers, the faint arcs -- dubbed SDSO 1 -- span nearly the same angular size as M31 itself. At first, their origin was a mystery: are they actually near the Andromeda Galaxy, or alternatively near to our Sun?

APOD: 2025 January 7 Б A New Years Aurora and SAR Arc
7.01.2025

It was a new year, and the sky was doubly red. The new year meant that the Earth had returned to its usual place in its orbit on January 1, a place a few days before its closest approach to the Sun.

Sun Pillar with Upper Tangent Arc
17.02.2021

This was not a typical sun pillar. Just after sunrise two weeks ago in Providence, Rhode Island, USA, a photographer, looking out his window, was suddenly awestruck. The astonishment was caused by a sun pillar that fanned out at the top.

APOD: 2023 July 17 Б Shells and Arcs around Star CW Leonis
17.07.2023

What's happening around this star? No one is sure. CW Leonis is the closest carbon star, a star that appears orange because of atmospheric carbon dispersed from interior nuclear fusion. But CW Leonis also appears engulfed in a gaseous carbon-rich nebula.

Arcs, Jets, and Shocks near NGC 1999
7.03.2018

This tantalizing array of nebulas and stars can be found about two degrees south of the famous star-forming Orion Nebula. The region abounds with energetic young stars producing jets and outflows that push through the surrounding material at speeds of hundreds of kilometers per second.

Colorful Arcs over Buenos Aires
15.12.2015

What are those colorful arcs in the sky? Like rainbows that are caused by rain, arcs of sunlight broken up into component colors can also result when ice crystals floating in Earth's atmosphere act together as a gigantic prism.

A Proton Arc Over Lake Superior
3.08.2015

The setting had been picked out -- all that was needed was an aurora. And late last August, forecasts predicted that an otherwise beautiful night sky would be lit up with auroral green. Jumping into...

Moon Corona, Halo, and Arcs over Manitoba
24.02.2020

Yes, but could you get to work on time if the Moon looked like this? As the photographer was preparing to drive to work, refraction, reflection, and even diffraction of moonlight from millions of falling ice crystals turned the familiar icon of our Moon into a menagerie of other-worldly halos and arcs.