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 Line Spread Functions

HST Spectroscopic Legacy Archive (HSLA)

COS Wavelength Tool

HST Exposure Time Calculator

Program Information

COS Instrument Resources

Recent News

Recently Published Documents

Instrument Science Reports (ISRs)


Recently Published ISRs

Listing Results

Results: 5

ISR 2019-19: Cycle 25 COS NUV Detector Dark Monitor

August 19, 2019C. Magness

ISR 2019-18: Cycle 25 COS FUV Spectroscopic Sensitivity Monitor

August 16, 2019R. Sankrit

ISR 2019-17: Cycle 25 COS FUV Detector Dark Monitor

August 13, 2019D. Dashtamirova

ISR 2019-11: Changes in the COS/FUV Dark Rate: Impact on the Monitoring Program and Background Extraction Regions

August 09, 2019D. Dashtamirova

ISR 2019-16: Cycle 25 COS FUV Wavelength Scale Monitor

August 07, 2019W. Fischer

View all ISRs

Newsletters (STANs)


Recently Published STANs

Listing Results

Results: 5

View all STANs

LAST UPDATED: 06/17/2019

Please Contact the HST Help Desk with any Questions