Secondary eclipse of Qatar-1b in the Ks band, showing the best-fitting model with ΔF = 0.186%, and Δφ = −0.0071. The detrended light curve is presented, where the small dots show the individual measurements. The solid line represents the best occultation model obtained from the joint-MCMC analysis, after removing the contribution of the systematics. The dotted vertical lines show the ingress and egress positions expected for circular orbit, and the dashed lines present ingress and egress found in the analysis. The filled circles show the light curve binned every 143 points (~9.5 min), for better visualization.