Waveform (left column) and Fourier spectrum (right column) of gravitational radiation from a point mass orbiting on the ISCO of a Schwarzschild BH (a = 0). All amplitudes are rescaled by r/μ, where r is the Boyer–Lindquist radial coordinate of the observer and μ the mass of the orbiting point. Three values of the colatitude θ of the observer are considered: θ = 0 (first row), θ = π/4 (second row) and θ = π/2 (third row).