def test_gal_to_equa(self):
for line in self.tevcat:
ra, dec = line[1]
l, b = line[3]
gal = astro.I3Galactic(l * I3Units.degree, b * I3Units.degree)
eq = astro.I3GetEquatorialFromGalactic(gal)
self.assertAlmostEqual(eq.ra / I3Units.degree, ra, 3)
self.assertAlmostEqual(eq.dec / I3Units.degree, dec, 3)
def test_gal_from_equa(self):
random.seed(0)
for n in range(10000):
eq = astro.I3Equatorial(random.uniform(0,2* math.pi),
random.uniform(-math.pi/2,math.pi/2),
)
gal = astro.I3GetGalacticFromEquatorial(eq)
eqprime = astro.I3GetEquatorialFromGalactic(gal)
self.assert_almost_equal(math.cos(eq.dec)*eq.ra ,math.cos(eqprime.dec)*eqprime.ra,1e-9)
self.assert_almost_equal(eq.dec,eqprime.dec,1e-10)
self.assert_less(astro.angular_distance(eq.ra,eq.dec,eqprime.ra,eqprime.dec),1e-10)
def test_equa_from_gal(self):
random.seed(0)
for n in range(10000):
gal = astro.I3Galactic(random.uniform(0,2*math.pi),
random.uniform(-math.pi/2,math.pi/2),
)
eq = astro.I3GetEquatorialFromGalactic(gal)
galprime = astro.I3GetGalacticFromEquatorial(eq)
self.assert_almost_equal(math.cos(gal.b)*gal.l,math.cos(galprime.b)*galprime.l,1e-9)
self.assert_almost_equal(gal.b,galprime.b,1e-10)
self.assert_less(astro.angular_distance(gal.l,gal.b,galprime.l,galprime.b),1e-10)
crab_direction.azimuth / I3Units.degree,
))
print
#the center of the galaxy is easy to remember in galactic coordinates
galaxy_center = astro.I3Galactic(0, 0)
print(
"The Galactic Center's galactic coordinates are l={:+8.4f} deg, b={:+7.4f} deg"
.format(
galaxy_center.l / I3Units.degree,
galaxy_center.b / I3Units.degree,
))
#convert to equatorial coordinates
gc_equatorial = astro.I3GetEquatorialFromGalactic(galaxy_center)
print(
"Which means its equatorial coordinates are ra={:8.4f} deg, dec={:+7.4f} deg"
.format(
gc_equatorial.ra / I3Units.degree,
gc_equatorial.dec / I3Units.degree,
))
#calculat the position of the galactic in local coordinates
gc_direction = astro.I3GetDirectionFromEquatorial(gc_equatorial, time)
print(
"At {} the Crab will be at zenith={:8.4f} deg, azimuth={:7.4f} deg".format(
str(time),
gc_direction.zenith / I3Units.degree,
gc_direction.azimuth / I3Units.degree,
))
def test_reference_points(self):
#Test the reference points that define the galactic coordinate system
#take from Wikipedia, the orignal paper was in B1950
#celestial north pole
eq = astro.I3Equatorial((12+51.4/60.)*15*I3Units.degree,
27.13 * I3Units.degree)
gal = astro.I3GetGalacticFromEquatorial(eq)
self.assertAlmostEqual(gal.b/I3Units.degree,+90,1)
#south pole
eq.ra = (+51.4/60.)*15*I3Units.degree
eq.dec = -27.13 * I3Units.degree
gal = astro.I3GetGalacticFromEquatorial(eq)
self.assertAlmostEqual(gal.b/I3Units.degree,-90,1)
#galactic center
eq.ra = (17+45.6/60.)*15*I3Units.degree
eq.dec = -28.94 * I3Units.degree
gal = astro.I3GetGalacticFromEquatorial(eq)
self.assertAlmostEqual(gal.b/I3Units.degree,0,1)
self.assertAlmostEqual(gal.l/I3Units.degree,360,1)
#anti-center
eq.ra = (5+45.6/60.)*15*I3Units.degree
eq.dec = +28.94 * I3Units.degree
gal = astro.I3GetGalacticFromEquatorial(eq)
self.assertAlmostEqual(gal.b/I3Units.degree,0,1)
self.assertAlmostEqual(gal.l/I3Units.degree,180,1)
#now test the reverse transform
#galactic north pole
gal = astro.I3Galactic( 0 * I3Units.degree,
+90 * I3Units.degree)
eq = astro.I3GetEquatorialFromGalactic(gal)
self.assertAlmostEqual(eq.ra/I3Units.degree,
(12+51.4/60.)*15.,1)
self.assertAlmostEqual(eq.dec/I3Units.degree,
27.13,1)
#south pole
gal.l = 0 * I3Units.degree
gal.b = -90 * I3Units.degree
eq = astro.I3GetEquatorialFromGalactic(gal)
self.assertAlmostEqual(eq.ra/I3Units.degree,
(0+51.4/60.)*15.,1)
self.assertAlmostEqual(eq.dec/I3Units.degree,
-27.13,1)
#galactic center
gal.l = 0 * I3Units.degree
gal.b = 0 * I3Units.degree
eq = astro.I3GetEquatorialFromGalactic(gal)
self.assertAlmostEqual(eq.ra/I3Units.degree,
(17+45.6/60.)*15.,1)
self.assertAlmostEqual(eq.dec/I3Units.degree,
-28.94,1)
#anti center
gal.l = 0 * I3Units.degree
gal.b = 180 * I3Units.degree
eq = astro.I3GetEquatorialFromGalactic(gal)
self.assertAlmostEqual(eq.ra/I3Units.degree,
(5+45.6/60.)*15.,1)
self.assertAlmostEqual(eq.dec/I3Units.degree,
+28.94,1)
#supergalactic north pole
sg = astro.I3SuperGalactic()
sg.b = 90 *I3Units.degree
sg.l = 0 *I3Units.degree
gal = astro.I3GetGalacticFromSuperGalactic(sg)
self.assertAlmostEqual(gal.l/I3Units.degree,
47.37,6)
self.assertAlmostEqual(gal.b/I3Units.degree,
6.32,6)
eq = astro.I3GetEquatorialFromSuperGalactic(sg)
print(eq.ra/I3Units.degree/15,eq.dec/I3Units.degree)
self.assertAlmostEqual(eq.ra/I3Units.degree,
18.92*15,1)
self.assertAlmostEqual(eq.dec/I3Units.degree,
15.7,1)
#supergalactic origin
sg = astro.I3SuperGalactic()
sg.b = 0 *I3Units.degree
sg.l = 0 *I3Units.degree
gal = astro.I3GetGalacticFromSuperGalactic(sg)
self.assertAlmostEqual(gal.l/I3Units.degree,
137.37,6)
self.assertAlmostEqual(gal.b/I3Units.degree,
0,6)
eq = astro.I3GetEquatorialFromSuperGalactic(sg)
self.assertAlmostEqual(eq.ra/I3Units.degree,
2.82*15,1)
self.assertAlmostEqual(eq.dec/I3Units.degree,
59.5,1)