Evolution of the 2D location ϕ_ℓ, t of a source in a speckle-aligned ASDI dataset: ϕ₀ defines the 2D angular location of a point source in a reference frame; the apparent location of the point source in the tth observation and the ℓth spectral band is indicated by a black disk; the apparent locations of a point source at other observation times and spectral bands are indicated by gray circles. The location ϕ_ℓ, t describes a radial motion with the wavelength and a rotation about the optical axis over time.