X Ray Stars of 47 Tucanae
24.05.2001

A deep optical image (left) of 47 Tucanae shows an ancient globular star cluster so dense and crowded that individual stars can not be distinguished in its closely packed core. An x-ray image of its central regions (inset right) from the Chandra Observatory reveals a wealth of x-ray stars hidden there.

Great Observatories Explore Galactic Center
11.11.2009

Where can a telescope take you? Four hundred years ago, a telescope took Galileo to the Moon to discover craters, to Saturn to discover rings, to Jupiter to discover moons, to Venus to discover phases, and to the Sun to discover spots.

The VLT Interferometric Array
9.03.1999

The Very Large Telescope (VLT) Interferometric Array will be able to act as individual telescopes or as one huge telescope. Of the four planned VLTs in Chile, two have now reached completion. The first VLT to operate is visible on the left of the above photograph and was recently given the name Antu.

Star Trails Above Mauna Kea
20.12.2005

Is there a road to the stars? Possibly there are many, but the physical road pictured above leads up to the top of a dormant volcano that is a premier spot on planet Earth for observing stars and astronomical phenomena.

X-Rays From Sirius B
6.10.2000

In visible light Sirius A (Alpha Canis Majoris) is the brightest star in the night sky, a closely watched celestial beacon throughout recorded history. Part of a binary star system only 8 light-years away, it was known in modern times to have a small companion star, Sirius B.

Comet Hale-Bopp Inbound
19.12.1996

Headed toward the inner Solar System, the much anticipated Comet Hale-Bopp has promised to put on a big show next spring. The comet's apparent brightness is currently approaching 4th magnitude and its inbound journey has been closely followed by many observers.

Tychos Supernova Remnant
17.03.2009

What star created this huge puffball? Pictured above is the best multi-wavelength image yet of Tycho's supernova remnant, the result of a stellar explosion first recorded over 400 years ago by the famous astronomer Tycho Brahe.

Hubble Floats Free
24.11.2002

Why put observatories in space? Most telescopes are on the ground. On the ground, you can deploy a heavier telescope and fix it more easily. The trouble is that Earth-bound telescopes must look through the Earth's atmosphere.

A GRB 000301C Symphony
14.03.2000

Telescopic instruments in Earth and space are still tracking a tremendous explosion that occurred across the universe. A nearly unprecedented symphony of international observations began abruptly on March 1 when Earth-orbiting RXTE, Sun-orbiting Ulysses, and asteroid-orbiting NEAR all detected a 10-second burst of high-frequency gamma radiation.

Compton Returns
7.03.2001

On 2000 June 4, the 17-ton Compton Gamma-Ray Observatory returned to Earth after 9 years in orbit -- ending its remarkable voyage of discovery. The massive, bus-sized spacecraft carried an unprecedented array of gamma-ray detectors which explored the bizarre, high-energy universe of solar flares, black holes, pulsars, supernovae, active galaxies, and gamma-ray bursts.