In [19]:

    

# get the data
import urllib
import astropy.io.fits as pyfits
lrgurl = 'http://www.sdss.org/dr5/algorithms/spectemplates/spDR2-028.fit'
urllib.urlretrieve(lrgurl,'spDR2-028.fit')
lrgobj = ('spDR2-028.fit')
lrgdata = pyfits.getdata(lrgobj)


    

In [32]:

    

spectrum = lrgdata[1,:] # 1 is "continuum-subtracted"


    

In [33]:

    

plot(spectrum)


    

    
Out[33]:





[<matplotlib.lines.Line2D at 0x108b90710>]






    

In [34]:

    

# sigh... can't really go on unless I have wavelength axis


    

In [35]:

    

import image_registration.iterative_zoom as iz


    

In [36]:

    

import scipy.signal


    

In [37]:

    

xc = scipy.signal.correlate(spectrum,spectrum,'full')


    

In [38]:

    

plot(xc)


    

    
Out[38]:





[<matplotlib.lines.Line2D at 0x108c2f0d0>]






    

In [78]:

    

reload(iz)
zoomed, zf, center = iz.iterative_zoom_1d(xc,minmax=np.max,mindiff=1e-10,verbose=True,return_zoomed=True,zoomshape=[50,],zoomstep=5)


    

    




Zoom factor      5, center =                           3554, offset=                             0, minpos=                          3554, mindiff=                   3.55271e-14

In [79]:

    

plot(zoomed)


    

    
Out[79]:





[<matplotlib.lines.Line2D at 0x10d189350>]






    

In [50]:

    




    

    
Out[50]:





-41.440239

In [ ]: