Difference in the gridded visibilities, where the gridded visibilities of the data after calibration using all baselines were subtracted from the gridded visibilities in all other scenarios (a) data before calibration, (b) calibration excluding baselines shorter than 300 wavelengths, and (c) calibration including all baselines and with a model for the large-scale diffuse structure. An inner disk with a radius of 300 wavelengths is clearly visible in (b), indicating an artificial increase in the values of this gridded visibilities within this disk.