Dithering utils - WIP

.travis.yml

@@ -91,3 +91,5 @@ cache:
     - $PANDIR/astrometry/
 after_success:
   - bash <(curl -s https://codecov.io/bash)
+after_failure:
+  - bash scripts/testing/failed-images-upload.sh ${POCS}/test_images/

pocs/tests/utils/test_dither.py

@@ -0,0 +1,191 @@
+import pytest
+import astropy.units as u
+from astropy.coordinates import SkyCoord
+from astropy.coordinates import Angle
+
+from pocs.utils import dither
+
+
+def test_dice9_SkyCoord():
+    base = SkyCoord("16h52m42.2s -38d37m12s")
+
+    positions = dither.get_dither_positions(base_position=base,
+                                            num_positions=12,
+                                            pattern=dither.dice9,
+                                            pattern_offset=30 * u.arcminute)
+
+    assert isinstance(positions, SkyCoord)
+    assert len(positions) == 12
+    # postion 0 should be the base position
+    assert positions[0].separation(base) < Angle(1e12 * u.degree)
+    # With no random offset positions 9, 10, 11 should be the same as 0, 1, 2
+    assert positions[0:3].to_string() == positions[9:12].to_string()
+    # Position 1 should be 30 arcminute offset from base, in declination direction only
+    assert base.spherical_offsets_to(
+        positions[1])[0].radian == pytest.approx(Angle(0 * u.degree).radian)
+    assert base.spherical_offsets_to(
+        positions[1])[1].radian == pytest.approx(Angle(0.5 * u.degree).radian)
+    # Position 3 should be 30 arcminute offset from base in RA only.
+    assert base.spherical_offsets_to(
+        positions[3])[0].radian == pytest.approx(Angle(0.5 * u.degree).radian)
+    assert base.spherical_offsets_to(
+        positions[3])[1].radian == pytest.approx(Angle(0 * u.degree).radian)
+
+
+def test_dice9_string():
+    base = "16h52m42.2s -38d37m12s"
+
+    positions = dither.get_dither_positions(base_position=base,
+                                            num_positions=12,
+                                            pattern=dither.dice9,
+                                            pattern_offset=30 * u.arcminute)
+
+    base = SkyCoord(base)
+
+    assert isinstance(positions, SkyCoord)
+    assert len(positions) == 12
+    # postion 0 should be the base position
+    assert positions[0].separation(base) < Angle(1e12 * u.degree)
+    # With no random offset positions 9, 10, 11 should be the same as 0, 1, 2
+    assert positions[0:3].to_string() == positions[9:12].to_string()
+    # Position 1 should be 30 arcminute offset from base, in declination direction only
+    assert base.spherical_offsets_to(
+        positions[1])[0].radian == pytest.approx(Angle(0 * u.degree).radian)
+    assert base.spherical_offsets_to(
+        positions[1])[1].radian == pytest.approx(Angle(0.5 * u.degree).radian)
+    # Position 3 should be 30 arcminute offset from base in RA only.
+    assert base.spherical_offsets_to(
+        positions[3])[0].radian == pytest.approx(Angle(0.5 * u.degree).radian)
+    assert base.spherical_offsets_to(
+        positions[3])[1].radian == pytest.approx(Angle(0 * u.degree).radian)
+
+
+def test_dice9_bad_base_position():
+    with pytest.raises(ValueError):
+        dither.get_dither_positions(base_position=42,
+                                    num_positions=42,
+                                    pattern=dither.dice9,
+                                    pattern_offset=300 * u.arcsecond)
+
+
+def test_dice9_random():
+    base = SkyCoord("16h52m42.2s -38d37m12s")
+
+    # Offsets don't have units so added as arcseconds
+    positions = dither.get_dither_positions(base_position=base,
+                                            num_positions=12,
+                                            pattern=dither.dice9,
+                                            pattern_offset=30 * 60,
+                                            random_offset=30)
+
+    assert isinstance(positions, SkyCoord)
+    assert len(positions) == 12
+    # postion 0 should be the base position
+    assert positions[0].separation(base) < Angle(30 * 2**0.5 * u.arcsecond)
+
+    angle_0 = Angle(0 * u.degree).radian
+    angle_05 = Angle(0.5 * u.degree).radian
+    angle_30 = Angle(30 * u.arcsecond).radian
+    position_1_offset = base.spherical_offsets_to(positions[1])
+    position_3_offset = base.spherical_offsets_to(positions[3])
+
+    # Position 1 should be 30 arcminute offset from base, in declination direction only
+    assert position_1_offset[0].radian == pytest.approx(angle_0, abs=angle_30)
+    assert position_1_offset[1].radian == pytest.approx(angle_05, abs=angle_30)
+
+    # Position 3 should be 30 arcminute offset from base in RA only.
+    assert position_3_offset[0].radian == pytest.approx(angle_05, abs=angle_30)
+    assert position_3_offset[1].radian == pytest.approx(angle_0, abs=angle_30)
+
+
+def test_random():
+    base = SkyCoord("16h52m42.2s -38d37m12s")
+
+    positions = dither.get_dither_positions(base_position=base,
+                                            num_positions=12,
+                                            random_offset=30 * u.arcsecond)
+    assert isinstance(positions, SkyCoord)
+    assert len(positions) == 12
+
+    angle_0 = Angle(0 * u.degree).radian
+    angle_30 = Angle(30 * u.arcsecond).radian
+    position_0_offset = base.spherical_offsets_to(positions[0])
+    position_1_offset = base.spherical_offsets_to(positions[1])
+
+    assert position_0_offset[0].radian == pytest.approx(angle_0, abs=angle_30)
+    assert position_0_offset[1].radian == pytest.approx(angle_0, abs=angle_30)
+
+    assert position_1_offset[0].radian == pytest.approx(angle_0, abs=angle_30)
+    assert position_1_offset[1].radian == pytest.approx(angle_0, abs=angle_30)
+
+
+def test_dice5():
+    base = SkyCoord("16h52m42.2s -38d37m12s")
+
+    positions = dither.get_dither_positions(base_position=base,
+                                            num_positions=12,
+                                            pattern=dither.dice5,
+                                            pattern_offset=30 * u.arcminute)
+
+    assert isinstance(positions, SkyCoord)
+    assert len(positions) == 12
+    # postion 0 should be the base position
+    assert positions[0].separation(base) < Angle(1e12 * u.degree)
+    # With no random offset positions 5, 6, 7 should be the same as 0, 1, 2
+    assert positions[0:3].to_string() == positions[5:8].to_string()
+    # Position 1 should be 30 arcminute offset from base, in RA and dec
+    assert base.spherical_offsets_to(
+        positions[1])[0].radian == pytest.approx(Angle(0.5 * u.degree).radian)
+    assert base.spherical_offsets_to(
+        positions[1])[1].radian == pytest.approx(Angle(0.5 * u.degree).radian)
+    # Position 3 should be 30 arcminute offset from base in RA and dec
+    assert base.spherical_offsets_to(positions[3])[0].radian == pytest.approx(
+        Angle(-0.5 * u.degree).radian)
+    assert base.spherical_offsets_to(positions[3])[1].radian == pytest.approx(
+        Angle(-0.5 * u.degree).radian)
+
+
+def test_custom_pattern():
+    base = SkyCoord("16h52m42.2s -38d37m12s")
+    cross = ((0, 0),
+             (0, 1),
+             (1, 0),
+             (0, -1),
+             (-1, 0))
+
+    positions = dither.get_dither_positions(base_position=base,
+                                            num_positions=12,
+                                            pattern=cross,
+                                            pattern_offset=1800 * u.arcsecond)
+
+    assert isinstance(positions, SkyCoord)
+    assert len(positions) == 12
+    # postion 0 should be the base position
+    assert positions[0].separation(base) < Angle(1e12 * u.degree)
+    # With no random offset positions 5, 6, 7 should be the same as 0, 1, 2
+    assert positions[0:3].to_string() == positions[5:8].to_string()
+    # Position 3 should be 30 arcminute offset from base, in declination direction only
+    assert base.spherical_offsets_to(
+        positions[3])[0].radian == pytest.approx(Angle(0 * u.degree).radian)
+    assert base.spherical_offsets_to(positions[3])[1].radian == pytest.approx(
+        Angle(-0.5 * u.degree).radian)
+    # Position 4 should be 30 arcminute offset from base in RA only.
+    assert base.spherical_offsets_to(positions[4])[0].radian == pytest.approx(
+        Angle(-0.5 * u.degree).radian)
+    assert base.spherical_offsets_to(
+        positions[4])[1].radian == pytest.approx(Angle(0 * u.degree).radian)
+
+
+# Note that the tolerance is way to high for this to be an effective test but
+# we are waiting on some clarity from the module.
+# https://github.com/matplotlib/pytest-mpl/issues/81
+@pytest.mark.mpl_image_compare(baseline_dir='baseline_images', tolerance=15)
+def test_plot_dither(tmpdir):
+    base = SkyCoord("16h52m42.2s -38d37m12s")
+    positions = dither.get_dither_positions(base_position=base,
+                                            num_positions=12,
+                                            pattern=dither.dice9,
+                                            pattern_offset=30 * u.arcminute)
+
+    dither_figure = dither.plot_dither_pattern(positions)
+    return dither_figure