The Simons Observatory (SO) is the largest next generation Cosmic Microwave Background
(CMB) experiment aimed to measure evidence of primordial gravitational waves and put
constraints on the sum of the neutrino masses through CMB polarization observations from
the ground. SO is developing a high angular resolution 6 m class Large Aperture
Telescope (LAT) for small angular scale measurements, and three wide field-of-view 0.42
m class Small Aperture Telescopes (SATs) for large angular scale measurements. Both
telescopes will be used to observe the CMB with unprecedented sensitivity from the
Atacama Desert in Chile. In total, SO will field over 60,000 transition-edge sensor
(TES) bolometers in six spectral bands centered between 27 and 280 GHz in order to
achieve the sensitivity necessary to measure or constrain numerous cosmological
quantities, as outlined in The Simons Observatory Collaboration et al. (2019).

In this talk I will introduce the plans and status of the SO experiment and on the
development of the SATs. I will further discuss the details of the optics design
development of the high-throughput SAT refractor system and telescope warm baffling.