beamcalcs.py

import numpy as np
import scipy as sp
import scipy.constants as const
import time
import datetime
import os

# MS file to use:
vis = 'L85562_all_flagged.MS'

r2asec = 206264.806

# Get list of subband center frequencies
tb.open(vis+'/SPECTRAL_WINDOW')
centerfqs = tb.getcol('REF_FREQUENCY')
tb.close()
# Convert to wavelength
centerlambda = const.c/centerfqs
# Get station diameter
tb.open(vis+'/ANTENNA')
diams = tb.getcol('DISH_DIAMETER')
tb.close()
diamsavg = np.mean(diams)

# Get max baseline
baselinesm = au.getBaselineLengths(vis, sort=True)
baselinesm1 = np.array(tuple(x[1] for x in baselinesm))
# Convert to wavelength
maxbaselines = baselinesm1.max()*np.ones((np.shape(centerlambda)[0], 1))/centerlambda

# Number of w-planes
dA = 0.5
nwplanes = (0.31/dA)*baselinesm1.max()*centerlambda/diamsavg

# Expected beamsize

FOV = centerlambda/diamsavg
FOVasec = FOV*r2asec
FOVamin = FOVasec/60
FOVdeg = FOVamin/60
synthbeam = centerlambda/baselinesm1.max()
synthbeamasec = synthbeam*r2asec