APOD: 2024 April 2 Б Detailed View of a Solar Eclipse Corona
2.04.2024

Only in the fleeting darkness of a total solar eclipse is the light of the solar corona easily visible. Normally overwhelmed by the bright solar disk, the expansive corona, the sun's outer atmosphere, is an alluring sight.

The Radio Sky: Tuned to 408MHz
20.10.2001

Tune your radio telescope to 408MHz (408 million cycles per second) and check out the Radio Sky! You should find that frequency on your dial somewhere between US broadcast television channels 13 and 14.

Orion over the Central Bohemian Highlands
18.02.2020

Do you recognize this constellation? Setting past the Central Bohemian Highlands in the Czech Republic is Orion, one of the most identifiable star groupings on the sky and an icon familiar to humanity for over 30,000 years.

Dark Nebulas across Taurus
14.03.2016

Sometimes even the dark dust of interstellar space has a serene beauty. One such place occurs toward the constellation of Taurus. The filaments featured here can be found on the sky between the Pleiades star cluster and the California Nebula.

Solstice Celebration
21.12.2002

Aloha and Season's greetings! On December 22nd, at 01:14 Universal Time (December 21, 3:14pm Hawaii-Aleutian Standard Time), the Sun reaches its southernmost point in planet Earth's sky marking the final season change for the year 2002. In celebration, consider this delightfully detailed, brightly colored image of the active Sun.

Exploring the Ring
18.09.2008

A familiar sight for northern hemisphere astronomers, the Ring Nebula (M57) is some 2,000 light-years away in the musical constellation Lyra. The central ring is about one light-year across, but this remarkably deep...

Rosetta s Rendezvous
7.08.2014

On August 3rd, the Rosetta spacecraft's narrow angle camera captured this stunning image of the nucleus of Comet 67P/Churyumov-Gerasimenko. After 10 years and 6.5 billion kilometers of travel along gravity assist trajectories looping through interplanetary space, Rosetta had approached to within 285 kilometers of its target.

Comet 46P Wirtanen
15.11.2018

Periodic Comet 46P/Wirtanen is now the brightest comet in the night sky, but too faint to be seen by eye. From dark sky sites it could just become naked-eye visible though, as it's 5.4 year long looping orbit takes it closest to Earth and the Sun in mid December.

APOD: 2025 June 2 Б Veil Nebula: Wisps of an Ancient Supernova
2.06.2025

Wisps like this are all that remain visible of a Milky Way star. About 7,000 years ago that star exploded in a supernova, leaving the Veil Nebula. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history.

A Sky Full Of Hydrogen
1.03.1998

Interstellar space is filled with extremely tenuous clouds of gas which are mostly Hydrogen. The neutral hydrogen atom (HI in astronomer's shorthand) consists of 1 proton and 1 electron. The proton and electron spin like tops but can have only two orientations; spin axes parallel or anti-parallel.