Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

NIST Stars

Several large telescope structures stand in the desert against a darkened sky.
Very Large Telescope, Cerro Paranal, Chile
Credit: ESO/B. Tafreshi

Telescope Details



Cerro Paranal, Chile, near the Very Large Telescope 


Astrophysicists use a network of “standard stars” for calibrating measurements of the absolute spectrum of light called flux by ground- and space-based telescopes. The data for current standard stars are based on 1970s terrestrial measurements of the star Vega, with uncertainties of a few percent and a tenuous link to the international system of units (the SI). The NIST Stars project aims to improve the accuracy of these data to meet requirements for modern astrophysics, approximately 0.1 % uncertainty over the visible-to-near-infrared spectrum with robust traceability to the SI.

NIST’s role:

Develop and operate an observatory, including a near-infrared telescope and spectrometer, to augment a similar system for visible light previously developed at Mount Hopkins, Arizona. The NIST Stars observatory in Chile is being designed to measure the absolute spectrum of flux from about 10 standard stars in the visible-to-near-infrared spectrum. The standard stars would be used for various applications such as making highly accurate measurements of special types of supernovae for studies of dark energy.

Significant discoveries:

At Mount Hopkins, NIST staff developed and deployed an accurate technique for measuring the absolute spectrum of flux from standard stars, with calibration traceable to the SI.  

Other interesting facts:

Significant technical advances in recent decades have enabled NIST to develop radiometric scales with just 0.01 % uncertainty for Earth-based measurements, far better than the level required by modern astrophysics. This project will enable NIST to extend SI-traceable measurement scales into the emerging realm of space in perpetuity. 

Supported by:


Operated by:

European Southern Observatory 


A white telescope on a red stand is outdoors with mountains in the background.
NIST Stars telescope
Credit: J. Woodward/NIST


Created May 12, 2022, Updated June 9, 2022