new_contents: # -*- coding: utf-8 -*-
  """
  =================================
  Drawing AIA Limb on STEREO Images
  =================================
  
  
  In this example we use a STEREO-B and an SDO image to demonstrate how to
  overplot the limb as seen by AIA on an EUVI-B image. This makes use of
  functionality added in Astropy 1.3.
  """
  
  ##############################################################################
  # Start by importing the necessary modules.
  
  from __future__ import print_function, division
  
  import numpy as np
  import matplotlib.pyplot as plt
  
  import astropy.units as u
  from astropy.coordinates import SkyCoord
  
  import sunpy.map
  import sunpy.coordinates
  import sunpy.coordinates.wcs_utils
  from sunpy.net import vso
  
  
  ##############################################################################
  # The first step is to download some data, we are going to get an image from
  # early 2011 when the STEREO spacecraft were roughly 90 deg seperated from the
  # Earth.
  
  stereo = (vso.attrs.Source('STEREO_B') &
            vso.attrs.Instrument('EUVI') &
            vso.attrs.Time('2011-01-01', '2011-01-01T00:10:00'))
  
  aia = (vso.attrs.Instrument('AIA') &
         vso.attrs.Sample(24 * u.hour) &
         vso.attrs.Time('2011-01-01', '2011-01-02'))
  
  wave = vso.attrs.Wave(30 * u.nm, 31 * u.nm)
  
  
  vc = vso.VSOClient()
  res = vc.query(wave, aia | stereo)
  
  
  ##############################################################################
  # The results from VSO query:
  
  print(res)
  
  
  ##############################################################################
  # Download the files:
  
  files = vc.get(res).wait()
  
  
  ##############################################################################
  # Create a dictionary with the two maps, cropped down to full disk.
  
  maps = {m.detector: m.submap((-1100, 1100) * u.arcsec,
                               (-1100, 1100) * u.arcsec) for m in sunpy.map.Map(files)}
  
  
  ##############################################################################
  # Calculate points on the limb in the AIA image for the half that can be seen
  # from STEREO.
  
  r = maps['AIA'].rsun_obs - 1 * u.arcsec # remove the one arcsec so it's on disk.
  # Adjust the following range if you only want to plot on STEREO_A
  th = np.linspace(-180*u.deg, 0*u.deg)
  x = r * np.sin(th)
  y = r * np.cos(th)
  
  coords = SkyCoord(x, y, frame=maps['AIA'].coordinate_frame)
  
  
  ##############################################################################
  # Plot both maps
  
  fig = plt.figure(figsize=(15, 5))
  ax1 = fig.add_subplot(1, 2, 1, projection=maps['AIA'])
  maps['AIA'].plot(axes=ax1)
  maps['AIA'].draw_limb()
  
  ax2 = fig.add_subplot(1, 2, 2, projection=maps['EUVI'])
  maps['EUVI'].plot(axes=ax2)
  ax2.plot_coord(coords, color='w')
  
subject: Add limb drawing example