December Sunrise, Cape Sounion
23.12.2009

The Sun is a moving target. Its annual motion through planet Earth's sky tracks north and south, from solstice to solstice, as the seasons change. On December 21st, the solstice marking the first...

Mariner's Mercury
6.09.1998

Mercury, the closest planet to the Sun, remains the most mysterious of the Solar System's inner planets. Hiding in the Sun's glare it is a difficult target for Earth bound observers.

Planetary Nebula Mz3: The Ant Nebula
5.02.2001

Why isn't this ant a big sphere? Planetary nebula Mz3 is being cast off by a star similar to our Sun that is, surely, round. Why then would the gas that is streaming away create an ant-shaped nebula that is distinctly not round?

Stars Without Galaxies
3.02.1997

Galaxies are made up of stars, but are all stars found within galaxies? Apparently not. Using the Hubble Space Telescope, researchers exploring the Virgo Cluster of galaxies have now found about 600 red giant stars adrift in intergalactic space.

Planetary Nebula Mz3: The Ant Nebula
1.05.2005

Why isn't this ant a big sphere? Planetary nebula Mz3 is being cast off by a star similar to our Sun that is, surely, round. Why then would the gas that is streaming away create an ant-shaped nebula that is distinctly not round?

Mars Opposition
27.07.2018

Look opposite the Sun in the sky tonight and you'll see Mars at its brightest. Also within days of its closest approach Mars rises at sunset, near its brightest and best for telescopic observers too, except for the dust storm still blanketing the Red Planet.

APOD: 2023 June 6 Б Star Eats Planet
6.06.2023

ItБs the end of a world as we know it. Specifically, the Sun-like star ZTF SLRN-2020 was seen eating one of its own planets. Although many a planet eventually dies by spiraling into their central star, the 2020 event, involving a Jupiter-like planet, was the first time it was seen directly.

APOD: 2024 April 8 Б The Changing Ion Tail of Comet Pons Brooks
8.04.2024

How does a comet tail change? It depends on the comet. The ion tail of Comet 12P/PonsБBrooks has been changing markedly, as detailed in the featured image sequenced over nine days from March 6 to 14 (top to bottom).

Blue Ghost s Diamond Ring
19.03.2025

On March 14 the Full Moon slid through Earth's dark umbral shadow and denizens of planet Earth were treated to a total lunar eclipse. Of course, from the Moon's near side that same astronomical syzygy was seen as a solar eclipse.

Midnight s Solar Eclipse
3.06.2011

On June 1, the shadow of the New Moon was cast across a land of the midnight Sun in this year's second partial solar eclipse. This picture of the geocentric celestial event above the Arctic Circle was taken near midnight from northern Finland's Kaunispää Hill in Lapland.