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22.2 Calibration Accuracy Resources

We will continue to update information under the "Calibration" area on the STIS Instrument World Wide Web (WWW) page which will help you to understand the accuracy you can achieve with your data at any given time. Among the types of information we provide there are the following.

The STIS web page can be found at:

http://www.stsci.edu/ftp/instrument_news/STIS/

The STIS Data Foibles Listing

The "STIS Data Foibles" page provides examples of commonly found data attributes and anomalies that are unique to STIS and that can affect the interpretation of your data. Currently described in this area are:

Fringing for CCD spectroscopic observations.
CCD long wavelength detector halo.
CCD Gain-4 detector noise.
CCD hot pixels.
CCD flat fields and "dust motes."
NUV-MAMA dark current.
Optical ghosts and artifacts in imaging mode.
Optical ghosts and artifacts in spectroscopic modes.
Echelle inter-order scatter.
MAMA PSF and LSF halos.

STIS Performance Summaries

On-orbit determined performance summaries will be updated on the web as information continues to become available. Currently we provide information under the Calibration page on:

Sensitivity measures and accuracies.
Target acquisitions.
MAMA detector performance.
CCD detector performance.
Point spread functions.
Line spread functions and spectral resolution.
Cross dispersion profiles.
Aperture locations and throughputs.
Geometric distortions.
MAMA flat fields.
Chronographic performance.
Instrument flexure, thermal stability.
Dispersion solutions and wavelength zeropoints.

Calibration Accuracy

We plan to maintain an up-to-date listing of the current levels of calibration accuracy provided by the pipeline at any one time, including such things as absolute sensitivity accuracy (by grating and central wavelength when applicable for spectroscopy and by filter for imaging modes), the relative sensitivity accuracies (across grating modes and across wavelengths within a giving grating mode), the aperture throughput accuracy, the absolute and relative wavelength accuracies and the astrometric accuracies, etc.

Pipeline Software History

The pipeline software history listing provides an ongoing log of the changes made to the calstis software and the implications for the accuracy of data calibrated with calstis. This history is useful if you are trying to decide whether you wish to download a new version of the calstis software.

Reference File History

The reference file listing provides a high-level summary of the history of updates to reference files, which can help you decide whether you wish to recalibrate your data.

Cycle 7 Calibration Plan

Here you can see what observations are planned for Cycle 7 calibration and which calibrations have already been taken. We note that all calibration data are non-proprietary. If we have not yet been able to process existing calibration data-especially data that are particularly appropriate for your science-into a reference file or a GO advisory, you can retrieve those datasets and analyze them directly yourself. New information about STIS instrument performance will be announced regularly in the STANs and posted to the STIS Instrument WWW pages.

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stevens@stsci.edu

Copyright © 1997, Association of Universities for Research in Astronomy. All rights reserved. Last updated: 07/01/98 10:49:41