fig = figure()
ax = fig.add_subplot(111)
ax.plot(T, r, 'b-', T, R, 'r-', T, r_geo, 'g-')
ax.set_yscale('log')
ax.annotate('Approx. sea level', xy=(Planet.T_day*1.3,(Planet.R)/1000), xytext=(Planet.T_day*1.3, Planet.R/1000))
ax.annotate('Geostat. orbit', xy=(Planet.T_day*1.3, r_geo[0]), xytext=(Planet.T_day*1.3, r_geo[0]))
ax.set_xlabel('Rotational period (hrs)')
ax.set_ylabel('Orbital radius (km), logarithmic')
ax.set_title('Orbital charts for ' + Planet.N, horizontalalignment='center', verticalalignment='top')
ax2 = ax.twiny()
ax2.plot(v,r,'k-')
ax2.set_xlabel('Linear speed (ms-1)')
show()