About COS

The Cosmic Origins Spectrograph (COS) was installed on the Hubble Space Telescope (HST) in May 2009. COS performs high-sensitivity, medium- and low-resolution spectroscopy of astronomical objects in the 815-3200 Å wavelength range. COS significantly enhances the spectroscopic capabilities of HST at ultraviolet wavelengths, providing observers with unparalleled opportunities for observing faint sources of ultraviolet light.

The primary science objectives of the instrument are the study of the origins of large scale structure in the Universe, the formation and evolution of galaxies, the origin of stellar and planetary systems, and the cold interstellar medium.

COS spectrum of a massive star in the LMC

This COS spectrum of a massive star in the LMC encodes information about the properties of its stellar wind, the intervening interstellar and circum-galactic media, enabling a wide range of legacy studies.


Current Status

COS/FUV is operating nominally.

COS/NUV is operating nominally.

Helpful Links

COS Wavelength Tool

HST Exposure Time Calculator

COS Instrument Handbook

COS Data Handbook

COS2025 Policies

COS Line Spread Functions

HST Spectroscopic Legacy Archive (HSLA)

Airglow Observations

Program Information

COS Instrument Resources

Recent News

Recently Published Documents

Instrument Science Reports (ISRs)


Recently Published ISRs

Listing Results

Results: 5

ISR 2020-04: Cycle 26 COS NUV Wavelength Scale Monitor

June 16, 2020W. Fischer

ISR 2020-03: Cycle 26 COS FUV Wavelength Scale Monitor

June 08, 2020W. Fischer

ISR 2020-02: Cycle 26 COS NUV Spectroscopic Sensitivity Monitor

June 08, 2020W. Fischer

ISR 2020-01: Summary of COS Cycle 26 Calibration Plan

May 29, 2020B. James

ISR 2019-07: The Lamp Template for the New COS/FUV Cenwave G160M/1533

November 14, 2019B. James

View all ISRs

Newsletters (STANs)


Recently Published STANs

Listing Results

Results: 5

February 2020 STAN

February 18, 2020

January 2020 STAN

January 28, 2020

October 2019 STAN

October 28, 2019

View all STANs

LAST UPDATED: 06/19/2020

Please Contact the HST Help Desk with any Questions