Aerial view of the CLASS site. The background image shows the CLASS site and its surrounding terrain; the two CLASS telescope mounts are slightly off-center. The direction toward neighboring CMB experiments on Cerro Toco: POLARBEAR, Atacama Cosmology Telescope (ACT), and the Simons Observatory (SO) are also labeled. Site camera locations and pointings are shown as black wedges, and their FoVs are delineated by the black border lines (solid borders for main cameras 1–3 and dashed ones for cameras that are daytime only). The shaded green region shows the footprint of the CLASS telescopes during the normal constant-elevation scan at 45°. Note that the telescope and camera FoVs are plotted in sky coordinates with the zenith at the center of the image, but the projection of the ground image centers at the nadir direction; therefore, the region enclosed by the site camera border lines do not reflect the actual view of the cameras (the inner border lines are the top edge of the camera images)—only the azimuthal information matches the sky coordinates.