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.


Program Information

COS Instrument Resources

Recent News

Recently Published Documents

Instrument Science Reports (ISRs)

Recently Published ISRs

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Results: 188
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  1. ISR 2023-26: Monitoring COS Spectral Placement after an OSM1 Home Position Move

    November 30, 2023J.H. Debes et al.
  2. ISR 2023-25: Overview of COS Lifetime Position 6 Calibration

    November 16, 2023R. Sankrit et al.
  3. ISR 2023-24: Investigating the Long-term Repeatability of the COS OSM1 Mechanism

    November 07, 2023S. Hasselquist et al.
  4. ISR 2023-23: Cycle 29 COS NUV Dark Monitor Summary

    October 30, 2023C.I. Johnson
  5. ISR 2023-22: Cycle 29 COS FUV Dark Monitor Summary

    October 16, 2023C.I. Johnson

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Newsletters (STANs)

Recently Published STANs

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Results: 31
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  1. January 2023 STAN

    January 04, 2023
  2. October 2022 STAN

    October 13, 2022

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Last Updated: 08/28/2023


HST Help Desk 

Please contact the HST Help Desk with any questions.