Straight up from the floor inside the drum of an observatory, curved walls of sulphur yellow, acid and bright steel-trowelled cement render catching the light in long sweeps filling the frame and running off all four edges. A helical stair is cantilevered across the view, the treads catching the light and the triangular voids beneath them dark. An elliptical oculus at the top holds one flat field of deep blue sky. The whole volume is flooded in its own bounced colour, two broad arcs of brighter glow rising from low in the wall, and the form reads through subtle value shifts alone. Clean, the surfaces smooth, the one optical event a soft halo around each lit source. Weightless and devotional, a room that looks up rather than out.