  The Simons Observatory (SO) will make precision temperature and polarization
measurements of the cosmic microwave background (CMB) over angular scales
between 1 arcminute and tens of degrees using over 60,000 detectors and
sampling frequencies between 27 and 270 GHz. SO will consist of a
six-meter-aperture telescope coupled to over 30,000 detectors and an array of
half-meter aperture refractive cameras, coupled to an additional 30,000+
detectors. The unique combination of large and small apertures in a single CMB
observatory will allow us to sample a wide range of angular scales over a
common survey area while providing an important stepping stone towards the
realization of CMB-Stage IV. CMB-Stage IV is a proposed project that will
combine and expand on existing facilities in Chile and Antarctica to reach the
~500,000 detectors required for CMB-Stage IV's science objectives. SO and
CMB-Stage IV will measure fundamental cosmological parameters of our universe,
constrain primordial fluctuations, find high redshift clusters via the
Sunyaev-Zeldovich 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 SO has led to innovative
instrumentation solutions which we will discuss. For instance, the SO large
aperture telescope will couple to a cryogenic receiver that is 2.4 m in
diameter and 2.4 m long. We will give an overview of the drivers for and
designs of the SO telescopes and cameras as well as the current status of the
project. We will also discuss the current status of CMB-Stage IV and important
next steps in the project's development.
