Yaw refers to motion in the y-direction of the telescope. Prior to October 2022, the case of the nominal dither period, the yaw was 1000 s for ACIS and 1087 s for HRC. After October 2022, the default for ACIS was increased to 2000 s. Table 5.4 in the POG gives the other default dither parameters in terms of pitch and yaw.