  The Simons Observatory (SO) will make precise temperature and polarization
measurements of the cosmic microwave background (CMB) using a set of telescopes
which will cover angular scales between 1 arcminute and tens of degrees,
contain over 60,000 detectors, and observe at frequencies between 27 and 270
GHz. SO will consist of a 6 m aperture telescope coupled to over 30,000
transition-edge sensor bolometers along with three 42 cm aperture refractive
telescopes, coupled to an additional 30,000+ detectors, all of which will be
located in the Atacama Desert at an altitude of 5190 m. The powerful
combination of large and small apertures in a CMB observatory will allow us to
sample a wide range of angular scales over a common survey area. SO will
measure fundamental cosmological parameters of our universe, constrain
primordial fluctuations, find high redshift clusters via the Sunyaev-Zel`dovich
effect, constrain properties of neutrinos, and trace the density and velocity
of the matter in the universe over cosmic time. The complex set of technical
and science requirements for this experiment has led to innovative
instrumentation solutions which we will discuss. The large aperture telescope
will couple to a cryogenic receiver that is 2.4 m in diameter and nearly 3 m
long, creating a number of technical challenges. Concurrently, we are designing
the array of cryogenic receivers housing the 42 cm aperture telescopes. We will
discuss the sensor technology SO will use and we will give an overview of the
drivers for and designs of the SO telescopes and receivers, with their cold
optical components and detector arrays.
