code: def cirs_radec(self, epoch):
          
          r_au, dec, ra = to_polar(self.cirs_xyz(epoch).au)
  
          return (Angle(radians=ra, preference='hours'),
                  Angle(radians=dec, signed=True),
                  Distance(r_au))
docs: Get spherical CIRS coordinates at a given epoch (ra, dec, distance).
  
          Calculate coordinates in the Celestial Intermediate Reference System
          (CIRS), a dynamical coordinate system referenced to the Celestial
          Intermediate Origin (CIO). As this is a dynamical system it must be
          calculated at a specific epoch.