Section of the window function W(ϕ_ij, t_j) in the frame that rotates at Ω_eq/2π = 453.1 nHz. At time t_j the longitudes of the travel times are denoted by ϕ_ij (see main text). The window function is equal to one for i ∈ { − 4, …4}, one half at the boundaries i = ±5, and zero elsewhere. The window function is also zero for missing data. The temporal periodicity of the window is 2π/(Ω_eq − Ω_⊕) = 27.46 days.