Backport fixes from astropy#14382

astropy/coordinates/tests/test_intermediate_transformations.py

@@ -1084,6 +1084,9 @@ def test_aa_hd_high_precision():
     Updated 2020-11-29, after the comparison between codes became even better,
     down to 100 nas.
 
+    Updated 2023-02-14, after IERS changes the IERS B format and analysis,
+    causing small deviations.
+
     NOTE: the agreement reflects consistency in approach between two codes,
     not necessarily absolute precision.  If this test starts failing, the
     tolerance can and should be weakened *if* it is clear that the change is
@@ -1105,8 +1108,9 @@ def test_aa_hd_high_precision():
     # Numbers from
     # https://github.com/astropy/astropy/pull/11073#issuecomment-735486271
     # updated in https://github.com/astropy/astropy/issues/11683
-    TARGET_AZ, TARGET_EL = 15.032673509956 * u.deg, 50.303110133923 * u.deg
-    TARGET_DISTANCE = 376252883.247239 * u.m
+    # and again after the IERS_B change.
+    TARGET_AZ, TARGET_EL = 15.032673662647138 * u.deg, 50.303110087520054 * u.deg
+    TARGET_DISTANCE = 376252.88325051306 * u.km
     assert_allclose(moon_aa.az, TARGET_AZ, atol=0.1 * u.uas, rtol=0)
     assert_allclose(moon_aa.alt, TARGET_EL, atol=0.1 * u.uas, rtol=0)
     assert_allclose(moon_aa.distance, TARGET_DISTANCE, atol=0.1 * u.mm, rtol=0)
@@ -1129,8 +1133,8 @@ def test_aa_high_precision_nodata():
     with a version of the code that passes the tests above, but for the internal solar system
     ephemerides to avoid the use of remote data.
     """
-    # Last updated when switching to erfa 2.0.0 and its moon98 function.
-    TARGET_AZ, TARGET_EL = 15.03231495 * u.deg, 50.3027193 * u.deg
+    # Last updated when the new IERS B format and analysis was introduced.
+    TARGET_AZ, TARGET_EL = 15.0323151 * u.deg, 50.30271925 * u.deg
     lat = -22.959748 * u.deg
     lon = -67.787260 * u.deg
     elev = 5186 * u.m
@@ -1139,8 +1143,8 @@ def test_aa_high_precision_nodata():
 
     moon = get_body("moon", t, loc)
     moon_aa = moon.transform_to(AltAz(obstime=t, location=loc))
-    assert_allclose(moon_aa.az - TARGET_AZ, 0 * u.mas, atol=0.55 * u.mas)
-    assert_allclose(moon_aa.alt - TARGET_EL, 0 * u.mas, atol=0.55 * u.mas)
+    assert_allclose(moon_aa.az - TARGET_AZ, 0 * u.mas, atol=0.5 * u.mas)
+    assert_allclose(moon_aa.alt - TARGET_EL, 0 * u.mas, atol=0.5 * u.mas)
 
 
 class TestGetLocationGCRS:

astropy/utils/iers/tests/test_iers.py

@@ -291,11 +291,11 @@ def test_simple(self):
             predictive_mjd = dat.meta["predictive_mjd"]
             dat._time_now = Time(predictive_mjd, format="mjd") + 7 * u.d
 
-            # Look at times before and after the test file begins.  0.1292905 is
+            # Look at times before and after the test file begins.  0.1292934 is
             # the IERS-B value from MJD=57359.  The value in
             # finals2000A-2016-02-30-test has been replaced at this point.
             assert np.allclose(
-                dat.ut1_utc(Time(50000, format="mjd").jd).value, 0.1293286
+                dat.ut1_utc(Time(50000, format="mjd").jd).value, 0.1292934
             )
             assert np.allclose(
                 dat.ut1_utc(Time(60000, format="mjd").jd).value, -0.2246227
@@ -306,7 +306,7 @@ def test_simple(self):
             # and an exception when extrapolating into the future with insufficient data.
             dat._time_now = Time(predictive_mjd, format="mjd") + 60 * u.d
             assert np.allclose(
-                dat.ut1_utc(Time(50000, format="mjd").jd).value, 0.1293286
+                dat.ut1_utc(Time(50000, format="mjd").jd).value, 0.1292934
             )
             with pytest.warns(
                 iers.IERSStaleWarning, match="IERS_Auto predictive values are older"
@@ -336,7 +336,7 @@ def test_simple(self):
         with iers.conf.set_temp("iers_auto_url", self.iers_a_url_2):
             # Look at times before and after the test file begins.  This forces a new download.
             assert np.allclose(
-                dat.ut1_utc(Time(50000, format="mjd").jd).value, 0.1293286
+                dat.ut1_utc(Time(50000, format="mjd").jd).value, 0.1292934
             )
             assert np.allclose(dat.ut1_utc(Time(60000, format="mjd").jd).value, -0.3)
 

docs/coordinates/frames.rst

@@ -231,10 +231,10 @@ set of coordinates, you will need to make sure that the shapes allow this::
       '2012-03-21T00:00:00.000']
      ['2012-06-21T00:00:00.000' '2012-06-21T00:00:00.000'
       '2012-06-21T00:00:00.000']], location=(3980608.90246817, -102.47522911, 4966861.27310068) m, pressure=0.0 hPa, temperature=0.0 deg_C, relative_humidity=0.0, obswl=1.0 micron): (az, alt) in deg
-        [[( 93.09845183, 89.21613128), (126.85789664, 25.4660055 ),
-          ( 51.37993234, 37.18532527)],
-         [(307.71713698, 37.99437658), (231.3740787 , 26.36768329),
-          ( 85.42187236, 89.69297998)]]>
+        [[( 93.09845155, 89.21613119), (126.85789646, 25.46600543),
+          ( 51.37993224, 37.1853252 )],
+         [(307.71713691, 37.99437664), (231.37407858, 26.36768334),
+          ( 85.42187562, 89.6929799 )]]>
 
 .. Note::
    Frames without data have a ``shape`` that is determined by their frame

docs/coordinates/spectralcoord.rst

@@ -460,7 +460,7 @@ T Tau. We can convert these frequencies to velocities assuming the Doppler shift
           redshift=0.0
         doppler_rest=115.2712018 GHz
         doppler_convention=radio)
-      [-11.90160353, -27.50828545, -30.1093991 ] km / s>
+      [-11.90160348, -27.50828539, -30.10939905] km / s>
 
 Note that these resulting velocities are different from the ``radial_velocity``
 property (which is still zero here) - the latter is the difference in velocity