Illustration of the used wavelet scales, Φ_DoB, fitted to to a synthetic RadioAstron uυ-coverage in image and Fourier domain. Scales of various radial widths (scales 3, 4, scales 5–9, and scale 10) and four different elliptical directions are shown. The scales are fit to the uυ-coverage, as they are sensitive to gaps or covered coefficients, respectively. Upper panel: Fourier transform of the wavelet scales and the synthetic RadioAstron uυ-coverage (red points). Lower panels: respective wavelet basis function in image domain.