As stated in
DM-9862, meas_mosaic assumes the 0,0 for each CCD to be the lower left hand corner. LSST uses a different coordinate system so meas_mosaic rotates the wcs into the LSST frame when writing to disk. However the photometric correction is still in the HSC frame, so when applying the meas_mosaic correction we need to rotate the wcs back to the HSC frame. We can then create the photometric correction, rotate it into the LSST frame and apply it to the image. We then rotate the wcs back to the LSST frame.