The Chandra X-ray Observatory is the U.S. follow-on to the Einstein
Observatory. Chandra was formerly known as AXAF, the Advanced X-ray
Astrophysics Facility, but renamed by NASA in December, 1998.
Originally three instruments and a high-resolution mirror carried in
one spacecraft, the project was reworked in 1992 and 1993. The Chandra
spacecraft carries a high resolution mirror, two imaging detectors,
and two sets of transmission gratings. Important Chandra features are:
an order of magnitude improvement in spatial resolution, good
sensitivity from 0.1 to 10 keV, and the capability for high spectral
resolution observations over most of this range.
The Hopkins Ultraviolet Telescope (HUT) was a shuttle-borne instrument used to obtain ultraviolet spectra in the far ultraviolet region of the spectrum. It was part of the ASTRO payload complement of three co-mounted instruments that flew in December 1990 and March 1995 as Space Shuttle missions. More than 650 spectra were obtained of 340 targets. In April, 2013, the HUT data was reprocessed to improve calibration, expand metadata, add new data products, and update file formats. The current cone service uses the metadata from these reprocessed files.
