Example 0.5 s sky and difference images in X polarization (scale of the color bar is in Jy) used to calculate SEFD. Left: 0.5 s sky image. Center: difference between two consecutive 0.5 s images. Right: difference between two consecutive 0.5 s images corrected for the primary beam (divided by the primary beam in the X polarization). In order to calculate noise in every direction in the sky within the field of view (noise map), the standard deviation of the noise was calculated in small regions around each pixel in the difference image and divided by . These noise maps were later converted into SEFD using Eq. (29). The same procedure was applied to Y and is very similar to Stokes I polarizations (in this case the correction for the primary beam was more complex than the simple division by the corresponding primary beam).