import astropy 
import numpy as np 
import matplotlib.pyplot as plt 
from astropy.visualization import astropy_mpl_style 
plt.style.use(astropy_mpl_style) 
from astropy.io import fits 
bdfile='http://www.astro.umd.edu/~jph/Python.d/BD30_STIS.d/sx2.d/o5ep03010_sx2.fits'
im = fits.getdata(bdfile, ext=1)
print(im.shape)
plt.figure()
plt.imshow(im, cmap='rainbow')
z=np.log(im)
plt.imshow(z, cmap='rainbow')
run h_strip
# the two density-dependant [O II] lines
sp=h_strip(im,550,600)
plt.figure()
plt.plot(sp,'b')

# the corresponding sp1 file              
file1='http://www.astro.umd.edu/~jph/Python.d/BD30_STIS.d/sx1.d/o5ep03010_sx1.fits'
im1 = fits.getdata(file1,ext=1)
fits.info(file1)
plt.figure()
wav1=(np.array(im1.WAVELENGTH))[0,:]
flx1=(np.array(im1.FLUX))[0,:]
plt.plot(wav1,flx1,'b')
sp1=hstrip(im1,575,625)
plt.figure()
plt.plot(sp1,'b')

np.sum(sp[764:774])
np.sum(sp[774:784]) 
sp2=h_strip(im,520,540)                                                 
np.sum(sp2[764:774])
np.sum(sp2[774:784])                                                    
sp3=h_strip(im,630,650)                                                 
np.sum(sp3[764:774])                                                    
np.sum(sp3[774:784])