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South Pole Telescope

A man in winter gear stands in front of a large dish with a background of snow and blue sky.
NIST’s Hannes Hubmayr at the South Pole Telescope
Credit: NIST

Telescope Details

Website

Location

Amundsen-Scott South Pole Station, Antarctica

Purpose

With a 10-meter primary mirror, the South Pole Telescope (SPT) is the largest millimeter-wave telescope dedicated to observing the cosmic microwave background (CMB) and can produce large-scale CMB maps at unparalleled resolution. 

NIST’s role

NIST has played a significant role in three generations of cameras, including the current one, providing sensors and electronics to collect sensor data. 

Significant discoveries and current status

The SPT helped make the first detection of the so-called B-mode lensing signal, which results when the gravity of massive objects distorts polarized light from the CMB before it reaches Earth. B-mode lensing provides information on the growth rate of large structures in the cosmos. It can also constrain the sum of the masses of the different types of neutrinos. This quantity is currently unknown.

Other interesting facts

With its unique location, the SPT also plays a critical role in the Event Horizon Telescope network, which for the first time imaged the event horizon around the black hole at the center of our galaxy. (NIST is not involved in the Event Horizon Telescope.)

Supported by

National Science Foundation, DOE Office of Science High Energy Physics, Kavli Institute for Cosmological Physics, U.S. Antarctic Program and Antarctic Support Contract

Media

Circular gold-colored plate has seven smaller circles in the center.
South Pole telescope sensor array
Credit: NIST

Contacts

Created October 7, 2021, Updated July 17, 2025
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