Observation scheme. We scanned ten heliocentric positions (μ = cosθ) from the disk center (DC, μ = 1.0) toward the solar limb (μ = 0.3) along the meridian (N–S) and equator (E–W): the north (blue circle), south (green rectangle), east (orange diamond), and west (red triangle) radian. The black ellipses indicate the field of view of LARS, the purple rectangle marks the HMI region for comparison.