code: def uv_to_Rz(u,v,delta=1.,oblate=False):
      
      if oblate:
          R= delta*sc.cosh(u)*sc.sin(v)
          z= delta*sc.sinh(u)*sc.cos(v)
      else:
          R= delta*sc.sinh(u)*sc.sin(v)
          z= delta*sc.cosh(u)*sc.cos(v)
      return (R,z)
docs: NAME:
  
         uv_to_Rz
  
      PURPOSE:
  
         calculate R and z from prolate confocal u and v coordinates
  
      INPUT:
  
         u - confocal u
  
         v - confocal v
  
         delta= focus
  
         oblate= (False) if True, compute oblate confocal coordinates instead of prolate
  
      OUTPUT:
  
         (R,z)
  
      HISTORY:
  
         2012-11-27 - Written - Bovy (IAS)
  
         2017-10-11 - Added oblate coordinates - Bovy (UofT)