The 60 inch Reflector
12.12.2008

On the night of December 13, 1908, 100 years ago today, the 60-inch diameter reflecting telescope of Mount Wilson Observatory was first tested on the stars. It became the first successful large reflecting telescope.

A Roll Cloud Over Uruguay
4.01.2010

What kind of cloud is this? A roll cloud. These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a cloud.

Supernova 1994D and the Unexpected Universe
30.05.2015

Long ago, far away, a star exploded. Supernova 1994D, visible as the bright spot on the lower left, occurred in the outskirts of disk galaxy NGC 4526. Supernova 1994D was not of interest for how different it was, but rather for how similar it was to other supernovae.

XZ Tauri System Ejects Gas Bubble
21.09.2000

Why is the binary star system XZ Tauri emitting a hot bubble of expanding gas? Although astronomers can only presently speculate, the Hubble Space Telescope clearly documents this unusual behavior in three dramatic photographs over the past five years.

Composing the Omega Nebula
10.12.2000

The Omega Nebula is a massive, complex cloud of dust and gas from which new stars are continually forming. The similarity to the Greek letter capital Omega gives the molecular cloud its popular name, but the nebula is also known as the Swan Nebula, the Horseshoe Nebula, and M17.

In the Heart of the Crab
5.06.2000

The supernova explosion that formed the Crab Nebula was first seen on the year 1054. Last week, astronomers released a new image of the still-evolving center of the explosion. The above representative-color photograph...

Molecular Cloud Barnard 68
1.02.2003

Where did all the stars go? What used to be considered a hole in the sky is now known to astronomers as a dark molecular cloud. Here, a high concentration of dust and molecular gas absorb practically all the visible light emitted from background stars.

NGC 6070: First Light for Sloan
10.06.1998

The graceful spiral galaxy NGC 6070, 100 million light-years distant in the constellation Serpens, is helping astronomers celebrate "First Light" (the first test sky images) for an exciting new telescope built to perform the ambitious Sloan Digital Sky Survey.

Leonids Above Torre de la Guaita
25.11.2000

Last year, the 1999 Leonids Meteor Shower came to a tremendous crescendo. Observers in Europe observed a sharp peak in the number of meteors visible around 0210 UTC during the early morning hours of November 18. Meteor counts then exceeded 1000 per hour - the minimum needed to define a true meteor storm.

Dim World, Dark Nebula
8.07.2010

Dim, distant, dwarf planet Pluto can be hard to spot, especially in recent months as it wanders through the crowded starfields of Sagittarius and the central Milky Way. But fortunately for backyard Pluto hunters, it crossed in front of a dark nebula in early July.