text: """Routines to download Earth orientation data."""
  
  import numpy as np
  import os
  from skyfield.api import load
  from skyfield.timelib import julian_date
  
  def morrison_and_stephenson_2004_table():
      """Table of smoothed Delta T values from Morrison and Stephenson, 2004."""
      import pandas as pd
      f = load.open('http://eclipse.gsfc.nasa.gov/SEcat5/deltat.html')
      tables = pd.read_html(f.read())
      df = tables[0]
      return pd.DataFrame({'year': df[0], 'delta_t': df[1]})
  
  def usno_historic_delta_t():
      import pandas as pd
      f = load.open('http://maia.usno.navy.mil/ser7/historic_deltat.data')
      df = pd.read_table(f, sep=b' +', engine='python', skiprows=[1])
      return pd.DataFrame({'year': df[b'Year'], 'delta_t': df[b'TDT-UT1']})
  
  def main():
      thisdir = os.path.dirname(__file__)
  
      df = morrison_and_stephenson_2004_table()
      year = df.year.values
      jd = julian_date(year, 1, 1)
      delta_t = df.delta_t.values
      array = np.array((jd, delta_t))
      np.save(os.path.join(thisdir, 'morrison_stephenson_deltat.npy'),
              array)
  
      df = usno_historic_delta_t()
      year = df.year.values
      jd = julian_date(year, 1, 1)
      delta_t = df.delta_t.values
      array = np.array((jd, delta_t))
      np.save(os.path.join(thisdir, 'historic_deltat.npy'),
              array)
  
  if __name__ == '__main__':
      main()
  