Transmission spectrum of Qatar-1b. Black circles and horizontal error bars show the derived R_P/R_S’s and their uncertainties. Horizontal lines are not error bars but indicate the size of the wavelength bin. Green, red and blue continuous lines correspond to Fortney et al. (2010) models for exo-atmospheres investigated in this work. Filled diamonds, squares and triangles indicate averages of the models within each wavelength bin. The models were artificially shifted to meet the data.