diff --git a/maoppy/test/test_psfmodel.py b/maoppy/test/test_psfmodel.py
index cb81075ceb216586b8aa45505e529f97d8f81659..2166333e56e30e5244e6ebc05d4bcad8b813cfbd 100644
--- a/maoppy/test/test_psfmodel.py
+++ b/maoppy/test/test_psfmodel.py
@@ -105,7 +105,7 @@ class TestPsfao(unittest.TestCase):
         npix = 1024
         samp = 2.0
         P = Psfao((npix,npix),system=ZIMPOL,samp=samp)
-        r0 = 0.15
+        r0 = 0.25
         C = 1e-4
         A = 1.0
         ax = 0.05
@@ -114,7 +114,8 @@ class TestPsfao(unittest.TestCase):
         beta = 1.5
         otf = P.otf([r0,C,A,ax,ay,theta,beta])
         mtf = np.max(np.abs(otf))
-        self.assertEqual(mtf,1.0)
+        self.assertAlmostEqual(mtf,1.0,delta=1e-2)
+        self.assertLessEqual(mtf,1.0)
         
         
         
diff --git a/maoppy_user_manual.pdf b/maoppy_user_manual.pdf
index 7b2755487988b462d26369264ce5918a1901dd43..52aa75f29f722c520d3adceeac3e26bb2355ad3f 100644
Binary files a/maoppy_user_manual.pdf and b/maoppy_user_manual.pdf differ