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-rwxr-xr-xastro/oskar/fits2skymodel.py13
1 files changed, 5 insertions, 8 deletions
diff --git a/astro/oskar/fits2skymodel.py b/astro/oskar/fits2skymodel.py
index a336515..e5b2ea3 100755
--- a/astro/oskar/fits2skymodel.py
+++ b/astro/oskar/fits2skymodel.py
@@ -32,7 +32,7 @@ from datetime import datetime
import numpy as np
import astropy.io.fits as fits
-import astropy.constants as ac
+import astropy.units as au
from astropy.wcs import WCS
@@ -106,14 +106,11 @@ class SkyModel:
def factor_K2JyPixel(self):
"""
Conversion factor to convert brightness unit from 'K' to 'Jy/pixel'
-
- http://www.iram.fr/IRAMFR/IS/IS2002/html_1/node187.html
"""
- pixarea = np.deg2rad(self.pixelsize/3600.0) ** 2 # [sr]
- kB = ac.k_B.si.value # Boltzmann constant [J/K]
- c0 = ac.c.si.value # speed of light in vacuum [m/s]
- freqHz = self.freq * 1e6 # [Hz]
- factor = 2*kB * 1.0e26 * pixarea * (freqHz/c0)**2
+ pixarea = (self.pixelsize * au.arcsec) ** 2
+ freq = self.freq * au.MHz
+ equiv = au.brightness_temperature(pixarea, freq)
+ factor = au.K.to(au.Jy, equivalencies=equiv)
return factor
@property