Venus and the Triply Ultraviolet Sun
20.08.2013

An unusual type of solar eclipse occurred last year. Usually it is the Earth's Moon that eclipses the Sun. Last June, most unusually, the planet Venus took a turn. Like a solar eclipse by the Moon, the phase of Venus became a continually thinner crescent as Venus became increasingly better aligned with the Sun.

Milky Way with Airglow Australis
3.09.2015

After sunset on September 1, an exceptionally intense, reddish airglow flooded this Chilean winter night skyscape. Above a sea of clouds and flanking the celestial Milky Way, the airglow seems to ripple and flow across the northern horizon in atmospheric waves.

Red Nebula, Green Comet, Blue Stars
19.12.2018

This festively colored skyscape was captured in the early morning hours of December 17, following Comet Wirtanen's closest approach to planet Earth. The comet was just visible to the eye. The lovely green...

APOD: 2024 June 12 Б Aurora over Karkonosze Mountains
11.06.2024

It was the first time ever. At least, the first time this photographer had ever seen aurora from his home mountains. And what a spectacular aurora it was. The Karkonosze Mountains in Poland are usually too far south to see any auroras.

APOD: 2025 July 8 Б The Pleiades in Red and Blue
7.07.2025

If you have looked at the sky and seen a group of stars about the size of the full Moon, that's the Pleiades (M45). Perhaps the most famous star cluster in the sky, its brightest stars can be seen even from the light-polluted cities.

Keck: The Largest Optical Telescopes
26.12.1997

In buildings eight stories tall rest mirrors ten meters across that are slowly allowing humanity to map the universe. Alone, each is the world's largest optical telescope: Keck. Together, the twin Keck telescopes have the resolving power of a single telescope 90-meter in diameter, able to discern sources just milliarcseconds apart.

NGC 2266: Old Cluster in the New General Catalog
29.04.1999

The New General Catalog of star clusters and nebulae really isn't so new. In fact, it was published in 1888 - an attempt by J. L. E. Dreyer to consolidate the work of astronomers William, Caroline, and John Herschel along with others into a useful single, complete catalog of astronomical discoveries and measurements.

NGC 1499: The California Nebula
24.09.2006

What's California doing in space? Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud by chance echoes the outline of California on the west coast of the United States.

The Horsehead Nebula
27.05.2007

One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s.

Zodiacal Light Vs Milky Way
11.02.2009

Two fundamental planes of planet Earth's sky compete for attention in this remarkable wide-angle vista, recorded on January 23rd. Arcing above the horizon and into the night at the left is a beautiful band of Zodiacal Light - sunlight scattered by dust in the solar system's ecliptic plane.