Monday, May 25, 2015
The South Pole Telescope
The South Pole Telescope (SPT) is a 10metre (394 in) diameter telescope located at the Amundsen Scott South Pole Station, Antarctica.
It’s designed for observations in the microwave, millimeter-wave, and submillimeter-wave regions of the electromagnetic spectrum, with the particular design goal of measuring the faint, diffuse emission from the cosmic microwave background (CMB).
The telescope is a Gregorian telescope, and is designed to allow a large field of view (about 1 square degree) while minimizing systematic uncertainties from ground spill-over and scattering off the telescope optics.
The surface of the telescope mirror is smooth down to roughly 25 micrometers (one thousandth of an inch), which allows sub-millimeter wavelength observations. The secondary mirror is cooled to 10 K, and metal mesh filters block excess high frequency radiation to keep the thermal loading on the camera down. A key advantage of the SPT observing strategy is that the entire telescope is scanned, so the beam does not move relative to the telescope mirrors. The fast scanning of the telescope and its large field of view makes SPT efficient at surveying large areas of sky, which is required to achieve the science goals of the SPT cluster survey and CMB polarization measurements.
In the winter the South Poles temperatures average -72 degrees Fahrenheit (-58 degrees Celsius), it is dark for six months, and it is really as dry as you can get on Earth.
This, however shitty it sounds, is the best spot on earth for astronomers, especially those who want to detect the tiny wavelengths of radiation that were created when the universe was young and new.
The first physical evidence that the universe expanded at a massive rate came from many years of observations from this point on earth.
“The South Pole is the closest you can get to space and still be on the ground,” said John Kovac of the Harvard-Smithsonian Center for Astrophysics in Massachusetts, “It’s one of the driest and clearest locations on Earth, perfect for observing the faint microwaves from the Big Bang.”
Source of info on The South Pole Telescope: Wikipedia & The south pole telescope blog.