X-Ray Pleiades

1999-08-28

The Pleiades star cluster is one of the jewels of the northern sky. To the unaided eye it appears as an alluring group of stars in the constellation Taurus, while telescopic views reveal cluster stars surrounded by delicate blue wisps of ...

Chandra's First Light: Cassiopeia A

1999-08-27

Cosmic wreckage from the detonation of a massive star is the subject of this official first image from NASA's Chandra X-ray Observatory. The supernova remnant, known as Cassiopeia A, was produced when a star exploded around 300 years ago in this ...

Cassini Flyby

1999-08-26 Gordon Garradd

Connect the dots and you'll trace the path of the Cassini spacecraft as it took a final turn by Earth on its way to the outer solar system. The dots (in a horizontal row just below center) are actually successive images of the spacecraft. The ...

Reflections on NGC 6188

1999-08-25 AAO

NGC 6188 is an interstellar carnival of young blue stars, hot red gas, and cool dark dust. Located 4000 light years away in the disk of our Galaxy, NGC 6188 is home to the Ara OB1 association, a group of bright young stars whose nucleus forms ...

A Network of Microlensing Caustics

1999-08-24 Joachim Wambsganss

A virtual sky map like this would be of interest to astronomers studying gravitational microlensing. In microlensing, the gravity of stars near the line of sight can act to magnify the light of background objects such as distant stars, or ...

Sundogs over the VLA

1999-08-23 Joe Orman

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, ...

The Center of Centaurus A

1999-08-22

A fantastic jumble of young blue star clusters, gigantic glowing gas clouds, and imposing dark dust lanes surrounds the central region of the active galaxy Centaurus A. This mosaic of Hubble Space Telescope images taken in blue, green, and red ...

Galaxies Away

1999-08-21

This striking pair of galaxies is far, far away ... about 350 million light-years from Earth. Cataloged as AM0500-620, the pair is located in the southern constellation Dorado. The background elliptical and foreground spiral galaxy are ...

Light From The Dark Sun

1999-08-19 Pavel and Roman Cagas

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

Sun Block

1999-08-18 Dominik Pasternak

During a total solar eclipse, Earth's moon blocks the sun - almost exactly. While the sun is about 400 times wider than the moon, it is also about 400 times farther away and each appears to be half a degree or so in diameter. On August 11, this ...