Schematic diagram illustrating the FoMo method for connecting the two grids: the original simulation grid (x, y, z) (gray in the diagram) and the grid (x′,y′,z′) in the observation reference frame (blue in in the diagram). Angle l is around the z-axis and angle b is around the y-axis. The gray and blue planes correspond to the planes perpendicular to the LoS, when it coincides with the z- and z′-axis, respectively. z^*-axis in the diagram represents the rotation around y. The red sphere represents the Sun at the center of the coordinate grid.