code: def dist_rhumb(ra1, dec1, ra2, dec2):
      
      # verified against website to give correct results
      phi1 = np.radians(dec1)
      phi2 = np.radians(dec2)
      dphi = phi2 - phi1
      lambda1 = np.radians(ra1)
      lambda2 = np.radians(ra2)
      dpsi = np.log(np.tan(np.pi / 4 + phi2 / 2) / np.tan(np.pi / 4 + phi1 / 2))
      if dpsi < 1e-12:
          q = np.cos(phi1)
      else:
          q = dpsi / dphi
      dlambda = lambda2 - lambda1
      if dlambda > np.pi:
          dlambda -= 2 * np.pi
      dist = np.hypot(dphi, q * dlambda)
      return np.degrees(dist)
docs: Calculate the Rhumb line distance between two points [1]_.
      A Rhumb line between two points is one which follows a constant bearing.
  
      Parameters
      ----------
      ra1, dec1, ra2, dec2 : float
          The position of the two points (degrees).
  
      Returns
      -------
      dist : float
          The distance between the two points along a line of constant bearing.
  
      Notes
      -----
      .. [1] `Rhumb line <https://en.wikipedia.org/wiki/Rhumb_line>`_