The most important discoveries of the new fleet of X-ray observatories are likely to be objects whose existence is unsuspected, these astronomers say.

Japan is concerned about the possible interference with its Astro-D X-ray observatory, which is scheduled to be launched next month.

Follow-up observations may be made by ground-based and space-based optical, radio, and X-ray observatories.

At its launch, Chandra was the most sophisticated X-ray observatory ever built.

Ross 154 is an X-ray source and it has been detected by several X-ray observatories.

Instead, they originate in Earth's geocorona or extended atmosphere which surrounds the orbiting X-ray observatory.

The European Space Agency plans to fly its own large X-ray observatory, a spacecraft called XMM.

The X-ray observatory, which is operated from the ground and has its own pointing system, also focused on Capella.

Though primarily an X-ray observatory, the satellite is also equipped to detect gamma rays.

Germany, for example, is building its own X-ray observatory, Rosat, to be launched in 1987.