Collinder 399: The Coat Hanger
23.12.2008

Is this coat hanger a star cluster or an asterism? This cosmic hang-up has been debated over much of last century, as astronomers wondered whether this binocular-visible object is really a physically associated open cluster or a chance projection. Chance star projections are known as asterisms, an example of which is the popular Big Dipper.

The Veil Nebula
16.09.2010

Delicate in appearance, these filaments of shocked, glowing gas, draped in planet Earth's sky toward the constellation of Cygnus, make up the Veil Nebula. The nebula is a large supernova remnant, an expanding cloud born of the death explosion of a massive star.

Collinder 399: The Coat Hanger
26.08.2015

Is this coat hanger a star cluster or an asterism? This cosmic hang-up has been debated over much of last century, as astronomers wondered whether this binocular-visible object is really a physically associated open cluster or a chance projection. Chance star projections are known as asterisms, an example of which is the popular Big Dipper.

Comet at Moonrise
4.10.2024

Comet C/2023 A3 (TsuchinshanБATLAS) is growing brighter in planet Earth's sky. Fondly known as comet A3, this new visitor to the inner Solar System is traveling from the distant Oort cloud. The comet...

Triple Conjunction Over Galician National Park
24.06.2015

What are those bright objects hovering over the horizon? Planets -- and the Moon. First out, the horizon featured is a shoreline of the Atlantic Ocean that occurs at the Galicia National Park in northern Spain. Next furthest out, on the left, is the Moon.

Williamina Fleming s Triangular Wisp
10.11.2017

Chaotic in appearance, these tangled filaments of shocked, glowing gas are spread across planet Earth's sky toward the constellation of Cygnus as part of the Veil Nebula. The Veil Nebula itself is a large supernova remnant, an expanding cloud born of the death explosion of a massive star.

A High Cliff on Comet Churyumov Gerasimenko
28.11.2021

This high cliff occurs not on a planet, not on a moon, but on a comet. It was discovered to be part of the dark nucleus of Comet Churyumov-Gerasimenko (CG) by Rosetta, a robotic spacecraft launched by ESA that rendezvoused with the Sun-orbiting comet in 2014.

Sundogs over the VLA
23.08.1999

What if you woke up one morning and saw more than one Sun in the sky? Most probably, you would be seeing sundogs, extra-images of the Sun created by falling ice-crystals in the Earth's atmosphere. As water freezes in the atmosphere, small, flat, six-sided, ice crystals might be formed.

X-Ray Moon
4.10.2003

This x-ray image of the Moon was made by the orbiting ROSAT (Röntgensatellit) Observatory in 1990. In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray moon, the darker half of the moon, and the x-ray sky background.

Unexpected Comet Pojmanski Now Visible
6.03.2006

Have you ever seen a comet? Comets bright enough to be visible to the unaided eye appear only every few years. Right now, however, a new comet has brightened unexpectedly and is visible as a faint streak to the unaided northern observer in the eastern morning sky just before sunrise. Binoculars may help.