def calc_image_uvw(vis_fname="test.fits", image_centre=[ 1.4596748494230258, 0.38422453855292943], savez=True):
print "will compute uvw"
f=FREQ2
h = pf.open(vis_fname)[1].header
tau = h['TSAMP']
toa = h['MJD']
dispersion_measure = h['DM']
print 'Have DM: ',dispersion_measure
antennas = h['ANTENNAS'].split('-')
tp=np.loadtxt('/home/user/IMAGING_FULL/antpos_ITRF.txt')
nants = len(antennas)
blen=np.zeros((nants*(nants-1)/2,3),dtype=np.float32)
u=np.zeros((NF2,nants*(nants-1)/2))
v=np.zeros((NF2,nants*(nants-1)/2))
w=np.zeros((NF2,nants*(nants-1)/2))
wcorr=np.zeros((NF2,nants*(nants-1)/2)) # This is the w correction for rotation of the phase centre
iiter=0
for i in range(nants-1):
for j in range(i+1,nants):
a1=int(antennas[i])-1; a2=int(antennas[j])-1;
blen[iiter,:]=np.array(tp[a1,1:]-tp[a2,1:])
iiter+=1
delays = dm_delay(f,dm=dispersion_measure)
t_mjd = toa + delays/SinD # SinD is seconds in a day defined in const.py
# t_mjd has the arrival time of pulses in each channel
print "TOA = "+str(toa)
print "Max disp delay = "+str(np.max(delays))
qa = casautil.tools.quanta()
me = casautil.tools.measures()
#me.doframe(me.observatory('DSA-10')) # Observatory (will look for entry in casacore measures:directory (see ~/.casarc)
me.doframe(me.observatory('OVRO_MMA')) # Observatory (will look for entry in casacore measures:directory (see ~/.casarc)
me.doframe(me.epoch('utc',qa.quantity(REF_EPOCH,'d')))
b=me.direction('HADEC', qa.quantity(0.0,'rad'),qa.quantity(POINTING,'rad'))
azel=me.measure(b,'AZEL')
me.doframe(me.epoch('utc',qa.quantity(toa,'d')))
radec=me.measure(azel,'J2000')
lst=radec['m0']['value']
dec=radec['m1']['value']
lam=C/f
for i in range(nants*(nants-1)/2):
tp4,tp5,tp6=fast_calc_uvw(blen[i,:],t_mjd,pointing=POINTING,src=[lst,dec])
tp1,tp2,tp3=fast_calc_uvw(blen[i,:],t_mjd,pointing=POINTING,src=[image_centre[0],image_centre[1]])
u[:,i]=tp1/lam
v[:,i]=tp2/lam
w[:,i]=tp3/lam
wcorr[:,i]=(tp3-tp6)/lam
#if savez:
#uv_fname = "%s_uvw.npz"%vis_fname[:-4]
#np.savez("test_withCasa.npz",u=u,v=v,w=w,wcorr=wcorr,f=f,t_mjd=t_mjd)
return u,v,w,wcorr
def calc_image_uvw(vis_fname="output.npz",
image_centre=[0., 0.],
savez=True,
act_image_centre=None):
print "will compute uvw"
f = FREQ1
h = np.load(vis_fname)
tau = h['TSAMP']
toa = h['MJD']
antennas = str(h['ANTENNAS']).split('-')
tp = np.loadtxt('/home/user/IMAGING_FULL/antpos_ITRF.txt')
nants = len(antennas)
blen = np.zeros((nants * (nants - 1) / 2, 3), dtype=np.float32)
u = np.zeros((len(toa), NF1, nants * (nants - 1) / 2))
v = np.zeros((len(toa), NF1, nants * (nants - 1) / 2))
w = np.zeros((len(toa), NF1, nants * (nants - 1) / 2))
wcorr = np.zeros(
(len(toa), NF1, nants * (nants - 1) /
2)) # This is the w correction for rotation of the phase centre
iiter = 0
for i in range(nants - 1):
for j in range(i + 1, nants):
a1 = int(antennas[i]) - 1
a2 = int(antennas[j]) - 1
blen[iiter, :] = np.array(tp[a1, 1:] - tp[a2, 1:])
iiter += 1
t_mjd = toa # has shape of time-samples
# do uvw calculation
lam = C / f
for i in range(nants * (nants - 1) / 2):
if act_image_centre is not None:
tp4, tp5, tp6 = fast_calc_uvw(
blen[i, :],
t_mjd,
pointing=POINTING,
src=[act_image_centre[0], act_image_centre[1]])
else:
tp4, tp5, tp6 = fast_calc_uvw(blen[i, :], t_mjd, pointing=POINTING)
tp1, tp2, tp3 = fast_calc_uvw(blen[i, :],
t_mjd,
pointing=POINTING,
src=[image_centre[0], image_centre[1]])
for j in range(len(toa)):
u[j, :, i] = tp1[j] / lam
v[j, :, i] = tp2[j] / lam
w[j, :, i] = tp3[j] / lam
wcorr[j, :, i] = (tp3[j] - tp6[j]) / lam
return u, v, w, wcorr
def calc_image_uvw(vis_fname="test.fits",
image_centre=[1.4596748494230258, 0.38422453855292943],
savez=True):
print "will compute uvw"
f = FREQ2
h = pf.open(vis_fname)[1].header
tau = h['TSAMP']
toa = h['MJD']
dispersion_measure = h['DM']
print 'Have DM: ', dispersion_measure
antennas = h['ANTENNAS'].split('-')
tp = np.loadtxt('/home/user/IMAGING_FULL/antpos_ITRF.txt')
nants = len(antennas)
blen = np.zeros((nants * (nants - 1) / 2, 3), dtype=np.float32)
u = np.zeros((NF2, nants * (nants - 1) / 2))
v = np.zeros((NF2, nants * (nants - 1) / 2))
w = np.zeros((NF2, nants * (nants - 1) / 2))
wcorr = np.zeros(
(NF2, nants * (nants - 1) /
2)) # This is the w correction for rotation of the phase centre
iiter = 0
for i in range(nants - 1):
for j in range(i + 1, nants):
a1 = int(antennas[i]) - 1
a2 = int(antennas[j]) - 1
blen[iiter, :] = np.array(tp[a1, 1:] - tp[a2, 1:])
iiter += 1
delays = dm_delay(f, dm=dispersion_measure)
t_mjd = toa + delays / SinD # SinD is seconds in a day defined in const.py
# t_mjd has the arrival time of pulses in each channel
print "TOA = " + str(toa)
print "Max disp delay = " + str(np.max(delays))
lam = C / f
for i in range(nants * (nants - 1) / 2):
tp4, tp5, tp6 = fast_calc_uvw(blen[i, :], t_mjd, pointing=POINTING)
tp1, tp2, tp3 = fast_calc_uvw(blen[i, :],
t_mjd,
pointing=POINTING,
src=[image_centre[0], image_centre[1]])
u[:, i] = tp1 / lam
v[:, i] = tp2 / lam
w[:, i] = tp3 / lam
wcorr[:, i] = (tp3 - tp6) / lam
return u, v, w, wcorr