def tophatbeam(loc,f,params):
cpc=params[0]
afwhm=params[1]
if(len(loc.shape)==1):
loc=np.array([loc])
output=np.ones(loc.shape[0])
output[geom.arc_length_list(loc,cpc)>afwhm]=0.
return output
def gaussbeam(loc,f,params):
if(len(loc.shape)==1):
loc=np.array([loc])
cpc=params[0]
afwhm=params[1]
sep=geom.arc_length_list(loc,cpc)
sigma=afwhm/np.sqrt(2.*np.log(2.))#*(180e6/f)
return np.exp(-.5*(sep/sigma)**2.)
def beamP(self,f):
#get the integrated beam power
if(self.bfunc.__name__=='tophatbeam'):
afwhm=self.params[1]
return pi*(np.radians(afwhm/2))**2.
elif(self.bfunc.__name__=='gaussbeam'):
afwhm=self.params[1]
sigma=np.radians(afwhm/np.sqrt(2.*np.log(2.)))#*(180e6/f))
return pi*sigma*sigma/2.
elif(self.bfunc.__name__=='cosbeam'):
afwhm=self.params[1]
return np.radians(afwhm)**2./pi**2.
elif(self.bfunc.__name__=='airybeam'):
a=self.params[1]
k=2*pi*f/c
return 4*pi/(k*a)*4.*integrate.quad(lambda x: (special.jn(1,np.sqrt(1-x**2.))/np.sqrt(1-x**2.))**2.,0,1)[0]
elif(self.bfunc.__name__=='mwabeam'):
#integrate mwabeam over theta and phi
obs=self.params[1]
pcentre=self.params[0]
pos=ephem.FixedBody()
pos._ra=np.radians(pcentre[0])
pos._dec=np.radians(pcentre[1])
pos.compute(obs)
az=float(repr(ephem.degrees(pos.az)))*180./np.pi
alt=float(repr(ephem.degrees(pos.alt)))*180./np.pi
cpc=[az,alt]
sep=geom.arc_length_list(mwaSweetSpots[:,:2],cpc)
delays=mwaSweetSpots[np.where(sep==sep.min())[0][0],3:].astype(int)
dip_sep=mwa_primary_beam._DIPOLE_SEPARATION
dipheight=mwa_primary_beam._DIPOLE_HEIGHT
def mwaBeamI(theta,phi):
rX,rY=mwa_primary_beam.MWA_Tile_analytic(theta,phi,freq=f,delays=delays,dipheight=dipheight,dip_sep=dip_sep,zenithnorm=True,power=True)
return (rX+rY)/2.*np.sin(theta)
return integrate.dblquad(mwaBeamI,0.,np.pi/2.,lambda x: 0., lambda x: 2.*np.pi)[0]
elif(self.bfunc.__name__=='heraBeam'):
fc=self.params[2]
df=self.params[1]
dPhi=np.radians(self.params[3])
dTheta=np.radians(self.params[4])
beamCube=self.params[5]
fInd=np.round((f-fc)/df)+beamCube.shape[0]/2
if(fInd>=0 and fInd<beamCube.shape[0]):
beamCube=beamCube*dPhi*dTheta
_,_,thetaCube=np.meshgrid(np.zeros(beamCube.shape[1]),np.zeros(beamCube.shape[0]),np.arange(beamCube.shape[2])*dTheta)
thetaCube=np.sin(thetaCube)
return np.sum((beamCube[fInd,:,:]*thetaCube[fInd,:,:]).flatten())
def airybeam(loc,f,params):
if(len(loc.shape)==1):
loc=np.array([loc])
a=params[1]/2#params 1 is the aperture DIAMETER
if(len(params)==3):
fc=params[2]
k=2*pi*fc/c
else:
k=2*pi*f/c
cpc=params[0]
sep=np.radians(geom.arc_length_list(loc,cpc))
x=k*np.sin(sep)*a
output=(2*special.jn(1,x)/x)**2.
output[sep==0.]=1.
return output
def mwabeam(loc,f,params):
#az,alt=obs.az,el(ra,dec)
obs=params[1]
pcentre=params[0]
#find az el of pointing centre
pos=ephem.FixedBody()
pos._ra=np.radians(pcentre[0])
pos._dec=np.radians(pcentre[1])
pos.compute(obs)
az=float(repr(ephem.degrees(pos.az)))*180./np.pi
alt=float(repr(ephem.degrees(pos.alt)))*180./np.pi
#find closets sweet splot
cpc=[az,alt]
# print 'center='+str(cpc)
sep=geom.arc_length_list(mwaSweetSpots[:,:2],cpc)
#print sep
delays=mwaSweetSpots[np.where(sep==sep.min())[0][0],3:].astype(int)
ra=loc[:,0]
dec=loc[:,1]
#azAlt=np.zeros(loc.shape)
pos=ephem.FixedBody()
# for ss in range(azAlt.shape[0]):
# pos._ra=np.radians(loc[ss,0])
# pos._dec=np.radians(loc[ss,1])
# pos.compute(obs)
# az=float(repr(ephem.degrees(pos.az)))
# alt=float(repr(ephem.degrees(pos.alt)))
# azAlt[ss,:]=az,alt
lst=np.degrees(float(repr(obs.sidereal_time())))
#print 'lat='+str(float(repr(obs.lat))*180./np.pi)
lat=float(repr(obs.lat))*180./np.pi
#print 'delays='+str(delays)
az,alt=ephem_utils.eq2horz(lst-ra,dec,lat)
theta=(90.-alt)*math.pi/180.
phi=az*math.pi/180.
dip_sep=mwa_primary_beam._DIPOLE_SEPARATION
dipheight=mwa_primary_beam._DIPOLE_HEIGHT
rX,rY=mwa_primary_beam.MWA_Tile_analytic(theta,phi,freq=f,delays=delays,dipheight=dipheight,dip_sep=dip_sep,zenithnorm=True,power=True)
#for now let's return the stokes sum
return (rX+rY)/2.
