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import astropy.io.fits as fits
import numpy as np
speed_of_light = 299792458. #m/s
def readData(filename, vis_name, pol):
hdu = fits.open(filename)
#reading in uvdata
print "Header..."
print hdu[0].header
print hdu[0].data['DATA'].shape
no_chan = hdu[0].data['DATA'].shape[3]
no_pol = hdu[0].data['DATA'].shape[4]
re = np.array([])
im = np.array([])
sigma = np.array([])
u = np.array([])
v = np.array([])
for chan in range(no_chan):
freq = hdu[0].header["CRVAL4"] + chan * hdu[0].header["CDELT4"]
if (np.count_nonzero(hdu[0].data['DATA'][:, 0, 0, chan, pol, 0]**2 + hdu[0].data['DATA'][:, 0, 0, chan, pol, 1]**2) > 0):
print "loading frequency ", freq, chan
flags = hdu[0].data['DATA'][:, 0, 0, chan, pol, 2]/np.abs(hdu[0].data['DATA'][:, 0, 0, chan, pol, 2]) #I think this gives the flags....
sigma = np.concatenate((sigma, 1./np.sqrt(hdu[0].data['DATA'][:, 0, 0, chan, pol, 2][flags > 0])))
re = np.concatenate((re, hdu[0].data['DATA'][:, 0, 0, chan, pol, 0][flags > 0]))
im = np.concatenate((im, hdu[0].data['DATA'][:, 0, 0, chan, pol, 1][flags > 0]))
#reading in uv-coordinates
u = np.concatenate((u, hdu[0].data['UU'][flags > 0] * freq))
v = np.concatenate((v, hdu[0].data['VV'][flags > 0] * freq))
print "Total visibilities... ", u.shape, v.shape, re.shape, im.shape, sigma.shape
#reading in weights
table = np.column_stack((u, v, re, im, sigma))
print table[0,:], u[0], v[0], re[0], im[0], sigma[0]
np.savetxt(vis_name, table, delimiter = " ")
names = ["0332-391", "0114-476", "1637-77", "sumss0515"]
for i in range(len(names)):
uv_fits = "/Users/luke/Radio_Data/" + names[i] +".uvfits"
output_vis = names[i] + ".vis"
readData(uv_fits, output_vis, 0)
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