where θ is the measured angle in arcseconds, Distance earth-sun is a constant (1 au or 1.5813 × 10 ly). The calculated stellar distance will be in the same measurement unit as used in Distance earth-sun (e.g. if Distance earth-sun = 1 au, unit for Distance star is in astronomical units; if Distance earth-sun = 1.5813 × 10 ly, unit for Distance star is in light-years).