Limiting magnitude at 5σ (diameter of the aperture = 2×FWHM) and 3σ surface brightness limit (10″×10″ area) as a function of the square root of the exposure time in the FUV (top) and NUV (bottom) images. With some scatter, the depth of the data follows nicely the theoretical expectation (${\mu }_{\lim }\propto t_{\exp }^{1/2}$). The numbers associated with the symbols indicate the NGC number of the galaxy observed by LIGHTS.