#154 (3)

use skyfield instead of astropy

packages/core/modules/enclosure_control.py

@@ -236,18 +236,17 @@ def auto_set_power_spectrometer(self) -> None:
         """
 
         current_sun_elevation = utils.Astronomy.get_current_sun_elevation(self.config)
-        min_power_elevation = (
-            self.config["general"]["min_sun_elevation"] - 1
-        ) * utils.Astronomy.units.deg
-
-        if current_sun_elevation is not None:
-            sun_is_above_minimum = current_sun_elevation >= min_power_elevation
-            if sun_is_above_minimum and (not self.plc_state["power"]["spectrometer"]):
-                self.plc_interface.set_power_spectrometer(True)
-                logger.info("Powering up the spectrometer.")
-            if (not sun_is_above_minimum) and self.plc_state["power"]["spectrometer"]:
-                self.plc_interface.set_power_spectrometer(False)
-                logger.info("Powering down the spectrometer.")
+        min_power_elevation = self.config["general"]["min_sun_elevation"] - 1
+        sun_is_above_minimum = current_sun_elevation >= min_power_elevation
+        spectrometer_is_powered = self.plc_state["power"]["spectrometer"]
+
+        if sun_is_above_minimum and (not spectrometer_is_powered):
+            self.plc_interface.set_power_spectrometer(True)
+            logger.info("Powering up the spectrometer.")
+
+        if (not sun_is_above_minimum) and spectrometer_is_powered:
+            self.plc_interface.set_power_spectrometer(False)
+            logger.info("Powering down the spectrometer.")
 
     def sync_cover_to_measurement_status(self) -> None:
         """Checks for flank changes in parameter measurement_should_be_running.

packages/core/modules/measurement_conditions.py

@@ -106,10 +106,7 @@ def _get_automatic_decision(self) -> bool:
             min_sun_elevation = max(
                 self._CONFIG["general"]["min_sun_elevation"], triggers["min_sun_elevation"]
             )
-            sun_above_threshold = current_sun_elevation > (
-                min_sun_elevation * utils.Astronomy.units.deg
-            )
-            if sun_above_threshold:
+            if current_sun_elevation > min_sun_elevation:
                 logger.debug("Sun angle is above threshold.")
             else:
                 logger.debug("Sun angle is below threshold.")

packages/core/modules/opus_measurement.py

@@ -258,26 +258,34 @@ def opus_application_running(self) -> bool:
         except _win32ui.error:
             return False
 
-    def low_sun_angle_present(self) -> bool:
+    def sun_angle_is_too_low(self) -> bool:
         """Checks defined sun angle in config. Closes OPUS at the end of the day to start up fresh
         the next day."""
 
         assert sys.platform == "win32"
 
-        sun_angle_is_low: bool = utils.Astronomy.get_current_sun_elevation(
-            self._CONFIG
-        ).is_within_bounds(
-            None, self._CONFIG["general"]["min_sun_elevation"] * utils.Astronomy.units.deg
+        return (
+            utils.Astronomy.get_current_sun_elevation(self._CONFIG)
+            < self._CONFIG["general"]["min_sun_elevation"]
         )
-        return sun_angle_is_low
 
     def automated_process_handling(self) -> None:
         """Start OPUS.exe if not running and sun angle conditions satisfied.
         Shuts down OPUS.exe if running and sun angle conditions not satisfied.
         """
         assert sys.platform == "win32"
 
-        if not self.low_sun_angle_present():
+        if self.sun_angle_is_too_low():
+            # Close OPUS if running
+            if self.opus_application_running():
+                logger.debug("Requesting OPUS night shutdown.")
+                # CLOSE_OPUS needs all macros closed to work. stop_macro() is
+                # called just in case
+                self.stop_macro()
+                time.sleep(5)
+                self.close_opus()
+
+        else:
             # start OPUS if not currently running
             if not self.opus_application_running():
                 logger.info("Start OPUS.")
@@ -287,15 +295,6 @@ def automated_process_handling(self) -> None:
                 self.load_experiment()
                 # returns to give OPUS time to start until next call of run()
                 return
-        if self.low_sun_angle_present():
-            # Close OPUS if running
-            if self.opus_application_running():
-                logger.debug("Requesting OPUS night shutdown.")
-                # CLOSE_OPUS needs all macros closed to work. stop_macro() is
-                # called just in case
-                self.stop_macro()
-                time.sleep(5)
-                self.close_opus()
 
     def wait_for_opus_startup(self) -> None:
         """Checks for OPUS to be running. Breaks out of the loop after a defined time."""

packages/core/threads/helios_thread.py

@@ -310,12 +310,9 @@ def main(headless: bool = False) -> None:
                     edge_fraction_history.set_max_size(new_max_history_size)
 
                 # sleep while sun angle is too low
-                if (not headless) and utils.Astronomy.get_current_sun_elevation(
-                    _CONFIG
-                ).is_within_bounds(
-                    None,
-                    _CONFIG["general"]["min_sun_elevation"] * utils.Astronomy.units.deg,
-                ):
+                current_sun_elevation = utils.Astronomy.get_current_sun_elevation(_CONFIG)
+                min_sun_elevation = _CONFIG["general"]["min_sun_elevation"]
+                if (not headless) and (current_sun_elevation > min_sun_elevation):
                     logger.debug("Current sun elevation below minimum: Waiting 5 minutes")
                     if current_state is not None:
                         interfaces.StateInterface.update(

packages/core/utils/astronomy.py

@@ -1,29 +1,26 @@
-from typing import Any
-import astropy.coordinates as astropy_coordinates
-import astropy.time as astropy_time
-import astropy.units as astropy_units
+from typing import Optional
+import skyfield.api
 from packages.core import types
 
-
-# TODO: replace this with a better library
+_PLANETS = skyfield.api.load("de421.bsp")
+_EARTH = _PLANETS["earth"]
+_SUN = _PLANETS["Sun"]
 
 
 class Astronomy:
     """Provides a method to compute the current sun elevation
     based on the coordinates from the CamTracker config file."""
 
-    units = astropy_units
-
     @staticmethod
-    def get_current_sun_elevation(config: types.ConfigDict) -> Any:
+    def get_current_sun_elevation(config: types.ConfigDict) -> float:
         """Computes current sun elevation in degree, based on the
         coordinates from the CamTracker config file."""
 
         with open(config["camtracker"]["config_path"], "r") as f:
             _lines = f.readlines()
 
         # find $1 marker
-        _marker_line_index = None
+        _marker_line_index: Optional[int] = None
         for n, line in enumerate(_lines):
             if line == "$1\n":
                 _marker_line_index = n
@@ -33,14 +30,13 @@ def get_current_sun_elevation(config: types.ConfigDict) -> Any:
         lon = float(_lines[_marker_line_index + 2].strip())
         alt = float(_lines[_marker_line_index + 3].strip())
 
-        now = astropy_time.Time.now()
-
-        altaz = astropy_coordinates.AltAz(
-            location=astropy_coordinates.EarthLocation.from_geodetic(
-                height=alt, lat=lat, lon=lon
-            ),
-            obstime=now,
+        current_time = skyfield.api.load.timescale().now()
+        current_position = _EARTH + skyfield.api.wgs84.latlon(
+            latitude_degrees=lat,
+            longitude_degrees=lon,
+            elevation_m=alt,
         )
-        sun = astropy_coordinates.get_sun(now)
-        sun_angle_deg = sun.transform_to(altaz).alt
-        return sun_angle_deg
+
+        sun_pos = current_position.at(current_time).observe(_SUN).apparent()
+        altitude, _, _ = sun_pos.altaz()
+        return float(altitude.degrees)

pyproject.toml

@@ -25,6 +25,7 @@ tqdm = "4.65.0"
 colorama = "0.4.6"
 deepdiff = "6.3.0"
 tum-esm-utils = "1.3.0"
+skyfield = "^1.46"
 
 [tool.poetry.group.dev.dependencies]
 pytest = "7.2.2"
@@ -58,7 +59,8 @@ module = [
     "snap7",
     "snap7.*",
     "deepdiff",
-    "psutil"
+    "psutil",
+    "skyfield.*"
 ]
 ignore_missing_imports = true