Cosmic Origins Spectrograph Instrument Handbook for Cycle 17

Chapter 1:
Introduction

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1.1 Purpose
    1.1.1 Document conventions
    1.1.2 FEFU: Femto-erg Flux Unit
1.2 Preparing Proposals and Observing with COS
    1.2.1 The STScI Spectrographs Branch and COS Team
    1.2.2 The STScI Help Desk
    1.2.3 COS web pages and supporting information
    1.2.4 Non-proprietary COS data

The Cosmic Origins Spectrograph (COS) is a fourth-generation instrument to be installed on the Hubble Space Telescope (HST) during Servicing Mission 4¹. COS is designed to perform high sensitivity, medium- and low-resolution spectroscopy of astronomical objects in the 1150-3200 Å wavelength range. COS will significantly enhance the spectroscopic capabilities of HST at ultraviolet wavelengths and will provide observers with unparalleled opportunities for observing faint sources of ultraviolet light. COS is not meant to be a replacement for the Space Telescope Imaging Spectrograph (STIS), which will remain in HST after the servicing mission². Both instruments have unique capabilities, which we describe and compare in this document.

This first chapter provides some basic information about this document and tells how to find additional information or help. The structure of the document is self-evident from the table of contents.

¹COS will be inserted into the HST bay currently housing COSTAR, the Corrective Optics Space Telescope Axial Replacement, which is no longer needed and has been out of use since SM3b.
²As this is written plans are also being made to repair STIS during SM4, restoring its unique capabilities to HST's repertoire.