Near-UV transmission spectrum of HD 189733 b from the combined HST/STIS observations. The red symbols with error bars denote the systematics- and stellar spot-corrected transmission spectrum, their 1σ uncertainties, and the span of the spectral bins for a resolving power of R =10. The blue spectrum shows a theoretical model of the planet’s upper atmosphere. The orange curve shows the fit to the optical–IR transmission spectrum extrapolated into the NUV; the shaded areas denote the 1σ and 2σ uncertainties. The black dashed curve shows the optical–IR fit shifted downward according to a SOFIA-like offset of ΔR_p/R_s = 0.001.