Preface

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This document describes the observing capabilities that are to be offered by the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) in a future Call for Proposals (Cycle 17 is anticipated). COS is not available for use during the current proposal cycle (Cycle 16). This document provides a brief preview of the COS instrument capabilities and comparisons with the capabilities of earlier generation instruments, such as the Space Telescope Imaging Spectrograph (STIS).

A more complete Instrument Handbook for COS will be provided as part of the Cycle 17 HST Call for Proposals. The sensitivities and specifications outlined in the present document should be treated as provisional since COS had not yet completed final pre-launch science calibration at the time this handbook was written.

Only minor changes have been made to this document from the previous version (2.0) issued three years ago. The technical information provided here is still valid and still reflects the best available estimate of expected on-orbit instrument performance. These data will be updated once results from further ground testing are available, but that will appear in a full-fledged COS Instrument Handbook.