Transmission spectra in the region of H α per night as calculated for the “Ingress” data (top) and “Egress” data (bottom). Nights are color coded as blue, orange, and green for night #1, #2 and #3 respectively. The vertical black dashed line corresponds to the laboratory wavelength of H α, with the red dashed line positioned at 6562.5Å, the position of the observed absorption feature. The black dashed horizontal line is the continuum level. Note that the “Egress” data for night #2 does not exist due to the partial transit observations.