Dynamic range and image quality improvement through self-calibration. The top two panels a–f show the improvement of imaging quality over multiple self-calibration iterations, demonstrated at 112.6 MHz with 1 s time integration and 1 MHz frequency averaging. White contour are drawn at 0.5%, 1%, 5%, 10%, 20%, 30%, 50%, 70%, and 90% of the peak intensity. The dashed yellow contour represents −1% of the peak intensity. The red ellipse in the bottom-left corner of each panel indicates the restoring beam. (a): Initial image (iteration 0), after applying only amplitude solutions from the calibrator and visibilities restricted to uv < 104 λ, allowing a simple Gaussian model to initiate phase-only self-calibration. (b): Image after first phase-only self-calibration using the Gaussian model; dynamic range (DR) improves to 106. (c): Phase-only self-calibration extended to uv < 254 λ for the second iteration further improves DR to 211. (d): After including baselines up to uv < 704 λ at iteration 5, DR increases to 343. (e): Final phase-only iteration with DR = 364. (f): Final image after amplitude-phase self-calibration converges; DR reaches 471. Bottom panel: Dynamic range variations across self-calibration cycles. Each point represents an iteration, and the maximum baseline length used (uv_max) is indicated in the figure. Phase-only calibration steps are shown in blue and yellow, amplitude-phase steps in red. Star markers indicate the best dynamic range achieved in each stage. The improvement in image fidelity through iterative self-calibration is evident.