The Simons Observatory is located in the high Atacama Desert in Northern Chile inside the Chajnator Science Preserve, at an altitude of 5,200 meters (17,000 ft).

The Atacama Cosmology Telescope (ACT) and the Simons Array[1] are located nearby and these experiments are currently making observations of the Cosmic Microwave Background (CMB).

The Simons Observatory shares many of the same goals but aims to take advantage of advances in technology to make far more precise and diverse measurements.

In addition, it is envisaged that many aspects of the Simons Observatory (optical designs, detector technologies and so on) will be pathfinders for the future CMB-S4 array.

[5][6][7] The observatory is named after the foundation and its founders: Jim Simons, the hedge fund billionaire and philanthropist who died on May 10, 2024 and his wife, Marilyn, a trained economist.

[8] One of the primary goals of the Simons Observatory are polarization maps of the sky with an order of magnitude better sensitivity than the Planck satellite.

Examples include gravitational lensing of the microwave background, the primordial bispectrum, and the thermal and kinematic Sunyaev-Zel'dovich effects.

To reduce systematic effects which become the dominant source of errors in very low noise maps, the Simons Observatory will build a 6-meter telescope and under illuminate the primary mirror to 5.5 meters.