Millennium Annular Solar Eclipse
21.01.2010

The Moon's shadow raced across planet Earth on January 15. Observers within the central shadow track were able to witness an annular solar eclipse as the Moon's apparent size was too small to completely cover the Sun.

Saturn at Opposition
28.05.2015

Telescopic observers on Earth have been treated to spectacular views of Saturn lately as the ringed planet reached its 2015 opposition on May 23 at 0200 UT. Of course opposition means opposite the Sun in Earth's sky. So near opposition Saturn is up all night, at its closest and brightest for the year.

APOD: 2025 July 17 Á 3I/ATLAS
16.07.2025

Discovered on July 1 with the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert, System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is so designated as the third known interstellar object to pass through our Solar System It follows 1I/éOumuamua in 2017 and the comet 2I/Borisov in 2019.

CMB Dipole: Speeding Through the Universe
27.01.2001

Our Earth is not at rest. The Earth moves around the Sun. The Sun orbits the center of the Milky Way Galaxy. The Milky Way Galaxy orbits in the Local Group of Galaxies. The Local Group falls toward the Virgo Cluster of Galaxies.

Jupiter and Io
28.11.2012

On December 3 (UT), Jupiter, the solar system's largest planet, will be at opposition, opposite the Sun in planet Earth's sky, shining brightly and rising as the Sun sets. That configuration results in Jupiter's almost annual closest approach to planet Earth.

A Starry Night of Iceland
4.01.2020

On some nights, the sky is the best show in town. On this night, the sky was not only the best show in town, but a composite image of the sky won an international competition for landscape astrophotography. The featured winning image was taken in 2011 over JÆkulsÀrlÑn, the largest glacial lake in Iceland.

APOD: 2023 February 21 Á Comet ZTF over Yosemite Falls
20.02.2023

They are both falling. The water in Yosemite Falls, California, USA, is falling toward the Earth. Comet ZTF is falling toward the Sun. This double cosmic cascade was captured late last month as fading Comet C/2022 E3 (ZTF) had just passed its closest to planet Earth. The orange star just over the falls is Kochab.

APOD: 2024 October 7 Á The Long Tails of Comet Tsuchinshan ATLAS
6.10.2024

A bright comet is moving into the evening skies. C/2023 A3 (TsuchinshanÁATLAS) has brightened and even though it is now easily visible to the unaided eye, it is so near to the Sun that it is still difficult to see. Pictured, Comet TsuchinshanÁATLAS was captured just before sunrise from an Andes Mountain in Peru.

Three Galaxies and a Comet
20.12.2023

Distant galaxies abound in this one degree wide field of view toward the southern constellation Grus (The Crane). But the three spiral galaxies at the lower right are quite striking. In fact, all three galaxies are grouped about 70 million light years away and sometimes known as the Grus Triplet.

An Iridescent Cloud Over Ohio
12.05.2009

Why would a cloud appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size.