Effect of observed velocity error on measurement of ν cos i and ν sin i on a solid body rotator with ν = 100 cy Gyr⁻¹. The statistically significant results (see Sect. 2.9) are represented by filled circles, and the corresponding 1σ errors are shown in the shaded areas. The horizontal lines show the measurements with no error. The typical errors in Gaia RV (1.3 km s⁻¹) and PM (0.02 km s⁻¹) are shown as dashed grey lines.