from IPython.core.display import HTML

with open('creative_commons.txt', 'r') as f:
    html = f.read()
    
name = '2013-10-28-ephem-ison'

html = """
<small>
<p> This post was written as an IPython notebook.  It is available for
<a href="https://ocefpaf.github.com/python4oceanographers/downloads/
notebooks/%s.ipynb">download</a> or as a static
<a href="https://nbviewer.ipython.org/url/ocefpaf.github.com/
python4oceanographers/downloads/notebooks/%s.ipynb">html</a>.</p>
<p></p>
%s """ % (name, name, html)

%matplotlib inline
from matplotlib import style
style.use('ggplot')

import ephem
import numpy as np
import matplotlib.pyplot as plt

ISON = "C/2012 S1 (ISON),h,11/28.7744/2013,62.3994,295.6528,345.5644,1.000002,0.012444,2000,7.5,3.2"
comet = ephem.readdb(ISON)
print(comet)

from pandas import DataFrame, date_range

days = date_range(start='2013/10/28', end='2013/12/31', freq='D')

earth_d, sun_d = [], [] 
for day in days:
    comet.compute(day)
    earth_d.append(comet.earth_distance)
    sun_d.append(comet.sun_distance)
    
df = DataFrame(np.c_[earth_d, sun_d], index=days, columns=['Earth', 'Sun'])

from scipy import constants
conversion = constants.au * 1e-3
df['Sun km'] = df['Sun'] * conversion
df['Earth km'] = df['Earth'] * conversion

df.head(5)

kw = dict(markeredgecolor='k', marker='o', linestyle='none')
arrowprops = dict(arrowstyle="->", connectionstyle="arc3,rad=.2", color='k')

fig, ax = plt.subplots(figsize=(8, 4))
sx, sy, sm = df['Sun'].argmin(), df['Sun'].min(), df['Sun km'].min()
ex, ey, em = df['Earth'].argmin(), df['Earth'].min(), df['Earth km'].min()

ax.plot(ex, ey, markerfacecolor='#339933', **kw)
ax.plot(sx, sy, markerfacecolor='#ff3333', **kw)

ax.annotate('Closest to Earth is\n%s km' % em,
            xy=(ex, ey), xycoords='data',
            xytext=(-20, 30), textcoords='offset points', arrowprops=arrowprops)

ax.annotate('Closest to the Sun is\n%s km' % sm,
            xy=(sx, sy), xycoords='data',
            xytext=(-180, 30), textcoords='offset points', arrowprops=arrowprops)

ax = df[['Earth', 'Sun']].plot(ax=ax, zorder=0, color=['#339933', '#ff3333'], linewidth=2)
_ = ax.set_ylabel('Distance [AU]')

obs = ephem.Observer()
obs.lon = np.deg2rad(-46.665)
obs.lat = np.deg2rad(-23.473)
obs.date = ex
comet.compute(obs)
print("Date: %s\nRight ascension: %s\nDeclination: %s\nMagnitude: %s" %
      (obs.date, comet.ra, comet.dec, comet.mag))

from IPython.display import YouTubeVideo
YouTubeVideo("A1yH_DuC88M", autoplay=0, theme="light", color="red")

HTML(html)