Top view of the AtLAST receiver cabin. The Cassegrain-mounted instruments are shown in red. The access platform for these instruments, which moves with the elevation rotating structure, is shown in green. The Nasmyth-mounted instruments (blue cylinders) are located on the yellow platforms, which do not move with the elevation rotating structure. Each Nasmyth platform has an area of 154 m². The receiver cabin area for the four Cassegrain instruments has a size of ~410 m², while the floor to ceiling height is ≈6.3 meters. Top views of average adult humans are shown for scale.