fix: amend UTC datetime.astimezone() across repository in @observerly…

…/celerity.

fix: amend UTC datetime.astimezone() across repository in @observerly/celerity.

src/celerity/equinox.py

@@ -26,9 +26,7 @@ def get_spring_equinox(year: int) -> datetime:
     )
 
     # Convert the Julian date to a datetime UTC object:
-    return datetime.utcfromtimestamp((JD - 2440587.5) * 86400).astimezone(
-        tz=timezone.utc
-    )
+    return datetime.fromtimestamp((JD - 2440587.5) * 86400).astimezone(tz=timezone.utc)
 
 
 # **************************************************************************************
@@ -49,9 +47,7 @@ def get_autumn_equinox(year: int) -> datetime:
     )
 
     # Convert the Julian date to a datetime UTC object:
-    return datetime.utcfromtimestamp((JD - 2440587.5) * 86400).astimezone(
-        tz=timezone.utc
-    )
+    return datetime.fromtimestamp((JD - 2440587.5) * 86400).astimezone(tz=timezone.utc)
 
 
 # **************************************************************************************

src/celerity/solstice.py

@@ -24,9 +24,7 @@ def get_summer_solstice(year: int) -> datetime:
     JD = 1721233.2486 + 365.2417284 * year - 0.053018 * pow(T, 2) + 0.009332 * pow(T, 3)
 
     # Convert the Julian date to a datetime UTC object:
-    return datetime.utcfromtimestamp((JD - 2440587.5) * 86400).astimezone(
-        tz=timezone.utc
-    )
+    return datetime.fromtimestamp((JD - 2440587.5) * 86400).astimezone(tz=timezone.utc)
 
 
 # **************************************************************************************
@@ -47,9 +45,7 @@ def get_winter_solstice(year: int) -> datetime:
     )
 
     # Convert the Julian date to a datetime UTC object:
-    return datetime.utcfromtimestamp((JD - 2440587.5) * 86400).astimezone(
-        tz=timezone.utc
-    )
+    return datetime.fromtimestamp((JD - 2440587.5) * 86400).astimezone(tz=timezone.utc)
 
 
 # **************************************************************************************

src/celerity/temporal.py

@@ -74,11 +74,8 @@ def get_greenwhich_sidereal_time(date: datetime) -> float:
     if T_0 < 0:
         T_0 += 24
 
-    # Ensure that the date is in UTC
-    d = date.astimezone(tz=timezone.utc)
-
     # Convert the UTC time to a decimal fraction of hours:
-    UTC = d.microsecond / 1e-6 + d.second / 60 + d.minute / 60 + d.hour
+    UTC = date.microsecond / 1e-6 + date.second / 60 + date.minute / 60 + date.hour
 
     A = UTC * 1.002737909
 
@@ -101,7 +98,7 @@ def get_local_sidereal_time(date: datetime, longitude: float) -> float:
     :param longitude: The longitude of the observer.
     :return: The Local Sidereal Time (LST) of the given date normalised to UTC.
     """
-    GST = get_greenwhich_sidereal_time(date.astimezone(tz=timezone.utc))
+    GST = get_greenwhich_sidereal_time(date)
 
     d = (GST + longitude / 15.0) / 24.0
 

tests/test_sun.py

@@ -1,6 +1,7 @@
 from datetime import datetime, timezone
 
 from src.celerity.common import EquatorialCoordinate, GeographicCoordinate
+from src.celerity.coordinates import convert_equatorial_to_horizontal
 from src.celerity.sun import (
     get_angular_diameter,
     get_distance,
@@ -65,6 +66,24 @@ def test_get_equatorial_coordinate():
     assert eq["ra"] == 318.5617376411268
     assert eq["dec"] == -16.008394691469505
 
+    hz = convert_equatorial_to_horizontal(date, observer, eq)
+
+    assert hz["alt"] == -69.40209879395105
+    assert hz["az"] == 82.77542830157664
+
+    # Add one hour to the date:
+    date = datetime(2015, 2, 5, 13, 0, 0, 0, tzinfo=timezone.utc)
+
+    eq = get_equatorial_coordinate(date)
+
+    assert eq["ra"] == 318.60368091333004
+    assert eq["dec"] == -15.995795336804742
+
+    hz = convert_equatorial_to_horizontal(date, observer, eq)
+
+    assert hz["alt"] == -55.32225076978145
+    assert hz["az"] == 89.64913544932578
+
 
 def test_get_angular_diameter():
     date = datetime(2015, 2, 15, 0, 0, 0, 0, tzinfo=timezone.utc)