Chapter 29 FOS Instrument Overview

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In This Chapter...

The Faint Object Spectrograph (FOS) was designed by the FOS Investigation Definition Team (IDT) consisting of Richard J. Harms (Principal Investigator), Roger Angel, Frank Barko, Edward Beaver, Ralph Bohlin, Margaret Burbidge, Arthur Davidsen, Holland Ford, and Bruce Margon. The instrument was built by the University of California, San Diego and prime subcontractor Martin Marietta Corporation Aerospace Division. A general overview of the instrument is given in Harms et al., 1982, in The Space Telescope Observatory, ed. by D.N.B. Hall (Washington:NASA), p.55.

There have been significant improvements in our understanding of the FOS. All FOS data should be recalibrated fully to assure that the latest and most accurate calibration files and the best algorithms are used.

We expect that, as more time passes since the removal of the FOS from HST in February 1997, the predominate users of these chapters will be archival researchers. These investigators may not be as familiar with FOS data and its assessment, calibration, and analysis as the original General Observers (GOs). Accordingly, we have included more detail about instrument operation, data assessment, and calibration than in previous versions of this handbook.

Five chapters are included in the FOS section:

• Chapter 29 gives a summary of the important sources of FOS information, apart from this handbook, a description of the instrument, an overview of the operational history and features of the FOS, and a brief introduction to FOS data-taking modes.
• Chapter 30 describes the basic structure of each important type of FOS data file. We present an overview of how to assess the quality of an FOS observation with detailed reference to the FOS paper products that have been re-designed to facilitate this activity. There are also examples of how to compare a planned observation with the dataset returned from the executed observation for the purpose of understanding anomalies.
• Chapter 31 includes a description of how data are calibrated in the Routine Science Data Processing (RSDP) pipeline and recalibrated with STSDAS, problems that can arise in this procedure, and how you should recalibrate your data with updated calibration files.
• Chapter 32 describes error sources and gives a statement of calibration accuracies.
• Chapter 33 considers several individual data analysis topics including description of some FOS-specific STSDAS tasks.
Although FOS was retired as an active instrument, STScI continues to provide analysis support for FOS data. Questions should be sent to help@stsci.edu. Any future updates to FOS documentation and calibration will be announced in the HST Spectrographs Space Telescope Analysis Newsletter (STAN).

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Last updated: 01/14/98 14:27:00