South Pole Telescope (SPT)
Located at the geographic south pole, the 10-m SPT is the largest telescope dedicated to studies of the cosmic microwave background (CMB), the oldest light in the Universe. We have just deployed the 3rd generation camera (SPT-3G), which will study the polarization of the CMB to measure gravitational lensing, the masses of neutrinos, and constrain the epoch of inflation.
We study high-redshift (2HST, Chandra, Spitzer, Herschel, APEX, ATCA, VLT, Gemini, and soon JWST. We use these to study intense star formation under "cosmic microscopes". We also use these sources as back-lights to directly image dark matter in the foreground lens.
The Terahertz Intensity Mapper (TIM)
This is an approved balloon program to do intensity mapping with ionized carbon. In other words, it will make 3D maps of the universe. It is a far-infrared spectrometer technology demonstrator for OST.