def test_combined_shifts_reduced_to_usable_number(self, sub_pix_frac):
ad_am_1_05 = eo._atmospheric_dispersion(airmass=1.05)
ad_am_neg_1_04 = eo._atmospheric_dispersion(airmass=-1.04)
shifts = fm_utils.get_3d_shifts([ad_am_1_05, ad_am_neg_1_04],
pixel_scale=0.004,
sub_pixel_fraction=sub_pix_frac)
assert len(shifts["y_shifts"]) == approx(10 / sub_pix_frac, rel=0.2)
def test_shifts_cancel_out_when_equal_and_opposite(self):
ad_am_1_05 = eo._atmospheric_dispersion(airmass=1.05)
ad_am_neg_1_05 = eo._atmospheric_dispersion(airmass=-1.05)
shifts = fm_utils.get_3d_shifts([ad_am_1_05, ad_am_neg_1_05],
pixel_scale=0.004,
sub_pixel_fraction=1)
assert len(shifts["y_shifts"]) == 2
assert np.min(shifts["wavelengths"]) == ad_am_1_05.meta["wave_min"]
assert np.max(shifts["wavelengths"]) == ad_am_1_05.meta["wave_max"]
def test_returns_almost_zero_for_zenith_atmospheric_dispersion(self):
ad_zenith = eo._atmospheric_dispersion(airmass=1.)
shifts = fm_utils.get_3d_shifts([ad_zenith],
pixel_scale=0.004,
sub_pixel_fraction=1)
assert np.all(shifts["x_shifts"] == 0)
assert np.all(shifts["y_shifts"] == 0)
def test_shift_transferred_to_x_axis_for_90_deg_pupil_angle(self):
ad_am_1_05 = eo._atmospheric_dispersion(airmass=1.05, pupil_angle=90)
shifts = fm_utils.get_3d_shifts([ad_am_1_05],
pixel_scale=0.004,
sub_pixel_fraction=1)
assert np.interp(0, shifts["x_shifts"][::-1],
shifts["wavelengths"][::-1]) == pytest.approx(1.5)
assert np.all(shifts["y_shifts"] == 0)
def test_returns_non_zero_entries_for_off_zenith(self):
ad_am_1_14 = eo._atmospheric_dispersion()
shifts = fm_utils.get_3d_shifts([ad_am_1_14],
pixel_scale=0.004,
sub_pixel_fraction=1)
assert np.all(shifts["x_shifts"] == 0)
assert np.interp(0, shifts["y_shifts"][::-1],
shifts["wavelengths"][::-1]) == pytest.approx(1.5)