Comparison of results of the measured R_p/R_s around the potassium doublet using different threshold levels to remove bad pixels and cosmic rays, and no seeing correction in the light curve fitting process. A lower threshold level could produce a spurious detection of an excess in the planet-to-star radius ratio near a deep telluric line as shown by blue squares. The blue and red data points do not present the trend in decreasing R_p/R_s between 750 nm and 870 nm as unlike the results shown in Figs. 9 and 10.