An error analysis for absolute flux density measurements of Cassiopeia A

An error analysis for absolute flux density measurement of radiosource Cas A is discussed. The lower-bound quadrature-accumulation error for state-of-the-art measurements of the absolute flux density of Cas A around 7 GHz is estimated to be 1.71 percent for 3σ limits. The corresponding practicable error for the careful but not state-of-the-art measurements is estimated to be 4.46 percent for 3σ limits.