Normalized spectra of the target (blue line) and comparison (red line). The black dashed vertical lines show the wavelength bins used to generate the spectroscopic light curves. The green vertical lines show the location of the sodium and potassium features, which are both encompassed within narrow bins (30 Å and 50 Å, respectively). Wavelengths outside of the range 4000–9000 Å were excluded due to low signal to noise.