Advanced X-ray Astrophysics Facility science instruments
Abstract
The AXAF science instruments (SIs) have undergone several changes since they were competitively selected in 1985. These changes stem from technical and scientific progress made during the instrument definition phase, the selection of a prime contractor for AXAF in 1988, and fiscal constraints required for the program. AXAF is the third of NASA's series of great observatories, following the Hubble Space Telescope (HST) and the Gamma Ray Observatory (GRO). Along with the Space Infrared Telescope (SIRTF) to follow AXAF, simultaneous studies of astrophysical phenomena will be possible over a broad range of wavelengths. AXAF will feature a grazing incidence telescope at one end of the observatory and accommodations for up to four SIs at the opposite end, each occupying a 90-degree sector at the telescope focus. The focal plane SIs selected for design and development include the high resolution camera (HRC), the AXAF CCD imaging spectrometer (ACIS), and the x-ray spectrometer (XRS). A possible fourth focal plane SI is the Bragg crystal spectrometer (BCS), currently in an extended definition phase through FY91. In addition to the focal plane SIs, there are two transmission grating spectrometers formed by inserting either high- or low- energy transmission gratings directly aft of the telescope and selecting one of the imaging SIs in order to detect spectral images. The SIs formed in this manner are called the high energy transmission grating spectrometer (HETGS) and the low energy transmission grating spectrometer (LETGS), respectively. This paper summarizes the overall AXAF program, giving particular emphasis to the SIs.
- Publication:
-
Space Astronomical Telescopes and Instruments
- Pub Date:
- September 1991
- DOI:
- 10.1117/12.46732
- Bibcode:
- 1991SPIE.1494..301W
- Keywords:
-
- Grazing Incidence Telescopes;
- Mirrors;
- Pointing Control Systems;
- X Ray Astrophysics Facility;
- Charge Coupled Devices;
- Imaging Spectrometers;
- Rosat Mission;
- Spacecraft Instrumentation