def ColumnD(S,T,kappa,a,d):
"""Takes inputs of; Flux (S in Jk), Temperature (T in Kelvin), oppacity (kappa in g cm-2), Number of pixels in distance (d in pcs)"""
#constants
au = 149597871000 #m
M_x = 1.989E30 #kg
m_h2 = 3.34745E-24 #g
mu = 2.333333 #ratio of H2 to He (5:1)
N = 1
#each pixel has an area in SI units and each apature contains N pixels
A = ((((a*d)*au)**2.0)*N)*10000 #in cm
M = mass.djr(S,T,kappa,d)
m = M*M_x*1000.0 #A = 1 density in g per pixel
n = m/(mu*m_h2*A) #column density per cm^2
N = m/A #density in g per cm^2
#print 'mass per pixel in solar masses:', M
#print 'column density of apature in per cm^2:', n
#print 'density of apature in g per cm^2:', N
return N
dMi_450 = mass_err(c450i,temp_mi,0.3)
dMi_850 = mass_err(c850i,temp_mi,0.02)
#Extract clump mass as number
cmd = '%s/stats ndf=%s %s'%(kapdir,mass450,'> /dev/null')
os.system(cmd)
cmd = '%s/parget parname=%s applic=%s'%(kapdir,'total','stats')
status, output = commands.getstatusoutput(cmd)
m450i = output
cmd = '%s/stats ndf=%s %s'%(kapdir,mass850,'> /dev/null')
os.system(cmd)
cmd = '%s/parget parname=%s applic=%s'%(kapdir,'total','stats')
status, output = commands.getstatusoutput(cmd)
m850i = output
print '850 mass by mean = ',mass.djr(float(c850i),float(temp_mi),kappa_4,d)
print '850 mass by pixel = ',m850i
#Run Stats and extract NUMBER of pixels
cmd = '%s/stats ndf=%s %s'%(kapdir,magic,'> /dev/null')
os.system(cmd)
cmd = '%s/parget parname=%s applic=%s'%(kapdir,'numgood','stats')
status, output = commands.getstatusoutput(cmd)
Ni = output
#Calculate effetive radii and append to file
Ni = float(Ni)
xxyy = a*d*(au/psc)
A = Ni*(xxyy**2.0)
ri = (A**0.5)/pi