Fix #1012: stop using deprecated utcnow()

Author: brandon-rhodes

CHANGELOG.rst

@@ -22,6 +22,9 @@ Unreleased future version
   reference frame was off by nearly 0.02 arcseconds because it applied
   precession but forgot to apply the frame tie between ICRS and J2000.
 
+* To avoid deprecation warnings on recent Pythons, Skyfield now avoids
+  Python’s old ``datetime.utcnow()`` method.
+
 v1.51 — 2025 February 23
 ------------------------
 

skyfield/tests/fixes.py

@@ -29,7 +29,7 @@ def setup(utc=(2015, 10, 11, 10)):
 
 def teardown():
     skyfield.api.load = skyfield.iokit.Loader('.')
-    skyfield.timelib.Timescale._utcnow = dt.datetime.utcnow
+    skyfield.timelib.Timescale._utcnow = skyfield.timelib._utcnow
     dt.datetime = _real_datetime_class
 
 class low_precision_ERA(object):

skyfield/tests/test_timelib.py

@@ -110,6 +110,10 @@ def test_time_creation_methods(ts, continuous_timescale, time_value):
     string = strftime('%S.%f')
     assert string == '37.500000'
 
+def test_now(ts):
+    t = ts.now()
+    assert isinstance(t, Time)
+
 def test_months_overflow_correctly(ts):
     assert ts.tt(2020, -1).tt_strftime('%Y-%m') == '2019-11'
     assert ts.tt(2020, 15).tt_strftime('%Y-%m') == '2021-03'

skyfield/timelib.py

@@ -49,6 +49,9 @@ def second(self): return self[5]
 
 if hasattr(dt_module, 'timezone'):
     utc = dt_module.timezone.utc
+    @staticmethod
+    def _utcnow():
+        return datetime.now(dt_module.UTC)
 else:
     class UTC(dt_module.tzinfo):
         'UTC'
@@ -61,6 +64,7 @@ def dst(self, dt):
             return self.zero
 
     utc = UTC()
+    _utcnow = datetime.utcnow
 
 # Much of the following code is adapted from the USNO's "novas.c".
 
@@ -89,7 +93,7 @@ class Timescale(object):
     timescale.
 
     """
-    _utcnow = datetime.utcnow
+    _utcnow = _utcnow
     polar_motion_table = None
 
     def __init__(self, delta_t_recent, leap_dates, leap_offsets):
@@ -123,14 +127,7 @@ def __init__(self, delta_t_recent, leap_dates, leap_offsets):
         self._leap_tai = self._leap_utc + self._leap_offsets
 
     def now(self):
-        """Return the current date and time as a `Time` object.
-
-        For the return value to be correct, your operating system time
-        and timezone settings must be set so that the Python Standard
-        Library constructor ``datetime.datetime.utcnow()`` returns a
-        correct UTC date and time.
-
-        """
+        """Return the current date and time as a `Time` object."""
         return self.from_datetime(self._utcnow().replace(tzinfo=utc))
 
     def from_datetime(self, datetime):