ROSAT

ROSAT (short for Röntgensatellit) was a German X-ray satellite telescope. It was named in honour of Wilhelm Röntgen. It was launched on June 1 1990 with a Delta II rocket from Cape Canaveral, and operated until February 12 1999.

From the NASA [http://nssdc.gsfc.nasa.gov/nmc/masterCatalog.do?sc=1990-049A web page on ROSAT] , with links added:

The Roentgensatellit (ROSAT) was a joint German, US and British X-ray astrophysics project. ROSAT carried a German-built imaging X-ray Telescope (XRT) with three focal plane instruments: two German Position Sensitive Proportional Counters (PSPC) and the US-supplied High Resolution Imager (HRI). The X-ray mirror assembly was a grazing incidence four-fold nested Wolter I telescope with an 84-cm diameter aperture and 240-cm focal length. The angular resolution was <5 arcsec at half energy width. The XRT assembly was sensitive to X-rays between 0.1 to 2 keV. In addition, a British-supplied extreme ultraviolet (XUV) telescope, the Wide Field Camera (WFC), was coaligned with the XRT and covers the wave band between and 6 angstroms (0.042 to 0.21 keV). ROSAT's unique strengths were high spatial resolution, low-background, soft X-ray imaging for the study of the structure of low surface brightness features, and for low-resolution spectroscopy. The ROSAT spacecraft was a three-axis stablized satellite which can be used for pointed observations, for slewing between targets, and for performing scanning observations on great circles perpendicular to the plane of the ecliptic. ROSAT was capable of fast slews (180 deg. in ~15 min.) which makes it possible to observe two targets on opposite hemispheres during each orbit. The pointing accuracy was 1 arcminute with stability <5 arcsec per sec and jitter radius of ~10 arcsec. Two CCD star sensors were used for optical position sensing of guide stars and attitude determination of the spacecraft. The post facto attitude determination accuracy was 6 arcsec. The ROSAT mission was divided into two phases: (1) After a two-month on-orbit calibration and verification period, an all-sky survey was performed for six months using the PSPC in the focus of XRT, and in two XUV bands using the WFC. The survey was carried out in the scan mode. (2) The second phase consists of the remainder of the mission and was devoted to pointed observations of selected astrophysical sources. In ROSAT's pointed phase, observing time was allocated to Guest Investigators from all three participating countries through peer review of submitted proposals. ROSAT had a design life of 18 months, but was expected to operate beyond its nominal lifetime.

"See also": X-ray astronomy

Highlights

* X-ray all-sky survey catalog, more than 150000 objects
* XUV all-sky survey catalog (479 objects)
* Source catalogs from the pointed phase (PSPC and HRI) containing ~ 100000 serendipitous sources
* Detailed morphology of supernova remnants and clusters of galaxies.
* Detection of shadowing of diffuse X-ray emission by molecular clouds.
* Detection of pulsations from Geminga.
* Detection of isolated neutron stars.
* Discovery of X-ray emission from comets.
* Observation of X-ray emission from the collision of Comet Shoemaker-Levy with Jupiter.

External links

* [http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1990-049A Overview of ROSAT]
* [http://www.n2yo.com/?s=20638&r=82358380296&dish A live view of where rosat is]

Trivia

* ROSAT was originally planned to be launched on the Space shuttle but the Challenger disaster caused it to be moved to the Delta platform.
* Originally designed for a 5 year mission, ROSAT continued in its extended mission for a further 4 years before equipment failure forced end of mission to be declared.