Remove SpiceKernels class, changing methods to functions (#69)

Remove SpiceKernels class, changing meths to funcs

See #68 for more details

CHANGELOG.md

@@ -20,6 +20,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Removed `SpiceKernel` as a class, lowering all its methods to the submodule level,
+  see #68 for more discussion.
 - Removed `Time` object which was a wrapper over astropy.Time, instead making a
   custom implementation of time which is ~3-400x faster than previous.
 - Improved orbital element conversion, leading to a 2-3x speedup in two body orbit

docs/tutorials/kona.rst

@@ -35,7 +35,7 @@ calculated from the corners of the frame.
     frame = fits.open("data/01772a127-w3-int-1b.fits.gz")[0]
 
     # Here we compute a State of the observer, this could also be constructed
-    # using spice kernels using neospy.SpiceKernels.state
+    # using spice kernels using neospy.spice.state
     sc_pos = neospy.Vector([frame.header['SUN2SCX'],
                             frame.header['SUN2SCY'],
                             frame.header['SUN2SCZ']],

docs/tutorials/propagation_plots.py

@@ -2,12 +2,12 @@
 import matplotlib.pyplot as plt
 import neospy
 
-neospy.SpiceKernels.kernel_reload(["./data/20000042.bsp"])
+neospy.spice.kernel_reload(["./data/20000042.bsp"])
 
 jd_start = neospy.Time.from_ymd(1920, 1, 1).jd
 jd_end = neospy.Time.from_ymd(2020, 1, 1).jd
 
-state = neospy.SpiceKernels.state("42", jd_end)
+state = neospy.spice.state("42", jd_end)
 
 jds = np.logspace(np.log10(jd_end), np.log10(jd_end - 10), 1000)
 jds = np.concatenate(
@@ -21,9 +21,9 @@
 error_2body = []
 n_body_no_asteroids = []
 n_body_ast = []
-state = neospy.SpiceKernels.state("42", jd_end)
+state = neospy.spice.state("42", jd_end)
 for jd in jds:
-    jpl_pos = neospy.SpiceKernels.state("42", jd).pos
+    jpl_pos = neospy.spice.state("42", jd).pos
 
     line = state.pos + state.vel * (jd - state.jd)
     error_line.append((jpl_pos - line).r * neospy.constants.AU_KM)

src/examples/galactic_center.py

@@ -36,7 +36,7 @@
 while states[0].jd < jd_end:
     states = neospy.propagate_two_body(states, states[0].jd + 1)
 
-    earth = neospy.SpiceKernels.state("Earth", states[0].jd)
+    earth = neospy.spice.state("Earth", states[0].jd)
 
     earth_to_obj = [(s.pos - earth.pos) for s in states]
     dist_to_galactic_center.append(

src/examples/on_sky.py

@@ -56,7 +56,7 @@
 print(obs_info)
 
 # Load the position of the observer in the solar system:
-observer = neospy.SpiceKernels.mpc_code_to_ecliptic("Palomar Mountain", jd)
+observer = neospy.spice.mpc_code_to_ecliptic("Palomar Mountain", jd)
 
 
 # %% Propagation and Orbit calculations

src/examples/plot_close_approach.py

@@ -40,7 +40,7 @@
     rel_earth_state = cur_state.change_center(399)
     pos.append([rel_earth_state.pos.x, rel_earth_state.pos.y])
     # gets earths position and record the distances.
-    moon = neospy.SpiceKernels.state("Moon", cur_state.jd, center=399).pos
+    moon = neospy.spice.state("Moon", cur_state.jd, center=399).pos
     dist_to_moon.append((moon - rel_earth_state.pos).r * neospy.constants.AU_KM)
     dist_to_earth.append(rel_earth_state.pos.r * neospy.constants.AU_KM)
     moon_pos.append([moon.x, moon.y])

src/examples/plot_close_encounter.py

@@ -29,7 +29,6 @@
 # Sample the time from start to end in 1 day steps
 jds = np.arange(jd_start, jd_end)
 
-eph = neospy.SpiceKernels()
 
 # Propagate the object to all of the state
 obj_pos = []
@@ -39,7 +38,7 @@
 for jd in jds:
     last_state = neospy.propagate_two_body([last_state], jd)[0]
     obj_pos.append(last_state.pos)
-    earth_pos.append(eph.state("Earth", jd).pos)
+    earth_pos.append(neospy.spice.state("Earth", jd).pos)
     earth_r.append(neospy.Vector(obj_pos[-1] - earth_pos[-1]).r)
 
 # Find the time where the closest encounter with the earth
@@ -56,10 +55,10 @@
 ax.plot(pos[0], pos[1], pos[2], alpha=0.5, color="black")
 ax.scatter(pos_center.x, pos_center.y, pos_center.z, s=5, color="black")
 for i, planet in enumerate(["Mercury", "Venus", "Earth", "Mars", "Jupiter"]):
-    states = [eph.state(planet, jd).pos for jd in jds]
+    states = [neospy.spice.state(planet, jd).pos for jd in jds]
     pos = np.array(states).T
     ax.plot(pos[0], pos[1], pos[2], color=f"C{i}", alpha=0.5)
-    pos = eph.state(planet, jd_center).pos
+    pos = neospy.spice.state(planet, jd_center).pos
     ax.scatter(pos.x, pos.y, pos.z, color=f"C{i}", s=5)
 ax.scatter(0, 0, 0, color="red")
 ax.set_xticks([-zoom, 0, zoom])

src/examples/plot_elevation.py

@@ -59,10 +59,8 @@
     # for each time step, calculate the elevation and sun elevation
     jd_step = jd_start + subrange
     approx_state = neospy.propagate_two_body(states, jd_step)
-    sun2obs = neospy.SpiceKernels.mpc_code_to_ecliptic(site, jd_step).pos
-    earth2obs = neospy.SpiceKernels.mpc_code_to_ecliptic(
-        site, jd_step, center="399"
-    ).pos
+    sun2obs = neospy.spice.mpc_code_to_ecliptic(site, jd_step).pos
+    earth2obs = neospy.spice.mpc_code_to_ecliptic(site, jd_step, center="399").pos
     sun_elevation.append(90 - earth2obs.angle_between(-sun2obs))
 
     cur_elev = []

src/examples/plot_light_curve.py

@@ -11,7 +11,7 @@
 
 
 # Using ceres as a source for a state vector
-state = neospy.SpiceKernels.state("ceres", 2460000.5)
+state = neospy.spice.state("ceres", 2460000.5)
 
 # Various input values
 albedo = 0.1
@@ -39,7 +39,7 @@
 
 for dt in dts:
     # Find the observer and object positions some time in the future.
-    earth_pos = neospy.SpiceKernels.state("Earth", jd + dt).pos
+    earth_pos = neospy.spice.state("Earth", jd + dt).pos
     final_pos = neospy.propagate_two_body([state], jd + dt, earth_pos)[0].pos
 
     obj2obs = final_pos - earth_pos

src/examples/plot_mpc_state.py

@@ -39,10 +39,10 @@
 # Plot the planets for 1 orbit each
 for i, planet in enumerate(["Mercury", "Venus", "Earth", "Mars", "Jupiter"]):
     jd = states[0].jd
-    plan = neospy.SpiceKernels().state(planet, jd)
+    plan = neospy.spice.state(planet, jd)
     ax.scatter(plan.pos.x, plan.pos.y, color=f"C{i}", s=10)
     jds = np.linspace(jd - plan.elements.orbital_period, jd, 100)
-    pos = np.array([neospy.SpiceKernels().state(planet, jd).pos for jd in jds]).T
+    pos = np.array([neospy.spice.state(planet, jd).pos for jd in jds]).T
     ax.plot(pos[0], pos[1], pos[2], color="black", alpha=0.2)
 
 for state in states:

src/examples/plot_observability.py

@@ -56,8 +56,8 @@
     # For each time, compute the geometry, then compute the mag as well as all of the
     # various angle and distance values.
     state = neospy.propagate_n_body([state], t)[0]
-    sun2obs = neospy.SpiceKernels.mpc_code_to_ecliptic(site, t).pos
-    earth2obs = neospy.SpiceKernels.mpc_code_to_ecliptic(site, t, center="399").pos
+    sun2obs = neospy.spice.mpc_code_to_ecliptic(site, t).pos
+    earth2obs = neospy.spice.mpc_code_to_ecliptic(site, t, center="399").pos
 
     sun2obj = state.pos
     obs2obj = -sun2obs + sun2obj
@@ -130,8 +130,8 @@
     nights = []
     for subrange in substeps:
         approx_state = neospy.propagate_two_body([state], t + subrange)[0]
-        sun2obs = neospy.SpiceKernels.mpc_code_to_ecliptic(site, t + subrange).pos
-        earth2obs = neospy.SpiceKernels.mpc_code_to_ecliptic(
+        sun2obs = neospy.spice.mpc_code_to_ecliptic(site, t + subrange).pos
+        earth2obs = neospy.spice.mpc_code_to_ecliptic(
             site, t + subrange, center="399"
         ).pos
 

src/examples/plot_phases.py

@@ -27,7 +27,7 @@
 # Move the entire population of asteroids to that time using 2-body
 # mechanics, this can be directly substituted with propagate_n_body if you
 # want more precision.
-sun2earth = neospy.SpiceKernels.state("Earth", jd).pos
+sun2earth = neospy.spice.state("Earth", jd).pos
 states = neospy.propagate_two_body(neos, jd)
 
 # Compute the expected V-mags for these objects at this time

src/examples/plot_trojans.py

@@ -16,7 +16,7 @@
 states = neospy.propagate_n_body(states, states[0].jd)
 
 # Where is jupiter?
-jupiter = neospy.SpiceKernels.state("Jupiter", states[0].jd)
+jupiter = neospy.spice.state("Jupiter", states[0].jd)
 # found it!
 
 # Compute the positions, and relative longitudinal distance from jupiter

src/examples/plot_uncertainty.py

@@ -50,7 +50,7 @@
 mags = []
 for jd in jds:
     states = neospy.propagate_n_body(states, jd)
-    earth = neospy.SpiceKernels.state("earth", jd)
+    earth = neospy.spice.state("earth", jd)
     m = [
         neospy.flux.hg_apparent_mag(
             sun2obj=x.pos, sun2obs=earth.pos, h_mag=obj.h_mag, g_param=g
@@ -65,7 +65,7 @@
 
 # position at lowest mag
 states = neospy.propagate_n_body(states, brightest_jd)
-earth = neospy.SpiceKernels.state("earth", brightest_jd)
+earth = neospy.spice.state("earth", brightest_jd)
 vecs = [(s.pos - earth.pos).as_equatorial for s in states]
 ras = np.array([v.ra for v in vecs])
 decs = np.array([v.dec for v in vecs])

src/neospy/__init__.py

@@ -18,8 +18,8 @@
     ztf,
     fov,
     shape,
+    spice,
 )
-from .spice import SpiceKernels
 from .propagation import (
     propagate_n_body,
     propagate_two_body,
@@ -64,12 +64,12 @@
     "population",
     "Time",
     "set_logging",
-    "SpiceKernels",
     "flux",
     "fov",
     "wise",
     "neos",
     "mpc",
+    "spice",
     "SimultaneousStates",
     "propagate_n_body",
     "propagate_two_body",

src/neospy/fov.py

@@ -16,7 +16,7 @@
     fov_spk_check as _fov_spk_check,
 )
 from .vector import State
-from .spice import SpiceKernels
+from . import spice
 
 
 __all__ = [
@@ -49,5 +49,5 @@ def fov_spice_check(desigs: list[str], fovs) -> list[State]:
     fov:
         A list of field of views from which to subselect objects which are visible.
     """
-    obj_ids = [SpiceKernels.name_lookup(n)[1] for n in desigs]
+    obj_ids = [spice.name_lookup(n)[1] for n in desigs]
     return _fov_spk_check(obj_ids, fovs)

src/neospy/mpc.py

@@ -920,7 +920,7 @@ def _read_first_line(line):
 
     @staticmethod
     def _read_second_line(line, jd):
-        from .spice import SpiceKernels
+        from . import spice
 
         if line[14] != "s":
             raise ValueError("No second line of spacecraft observation found.")
@@ -929,7 +929,7 @@ def _read_second_line(line, jd):
         y = float(line[46:57].replace(" ", "")) / constants.AU_KM
         z = float(line[58:69].replace(" ", "")) / constants.AU_KM
         earth2sc = Vector([x, y, z], Frames.Equatorial).as_ecliptic
-        sun2earth = SpiceKernels.state("Earth", jd).pos
+        sun2earth = spice.state("Earth", jd).pos
         sun2sc = sun2earth + earth2sc
         return list(sun2sc)
 

src/neospy/propagation.py

@@ -8,9 +8,8 @@
 from scipy import optimize
 import numpy as np
 
-from .spice import SpiceKernels
 from .vector import Vector, State
-from . import _core
+from . import _core, spice
 from ._core import NonGravModel
 
 
@@ -133,10 +132,10 @@ def moid(state: State, other: Optional[State] = None):
     state:
         The state describing an object.
     other:
-        The state of the object to calculate the MOID for, if this is not provided, then
-        Earth is fetched from :class:`~neospy.spice.SpiceKernels` and is used in
-        the calculation.
+        The state of the object to calculate the MOID for, if this is not provided,
+        then Earth is fetched from :mod:`~neospy.spice` and is used in the
+        calculation.
     """
     if other is None:
-        other = SpiceKernels.state("Earth", state.jd)
+        other = spice.state("Earth", state.jd)
     return _moid_single(state, other)

src/neospy/rust/time.rs

@@ -101,12 +101,6 @@ impl PyTime {
         PyTime(Time::<UTC>::from_year_month_day(year, month, day, frac_day).tdb())
     }
 
-    /// Time in the UTC ISO time format.
-    #[getter]
-    pub fn iso(&self) -> PyResult<String> {
-        Ok(self.0.utc().to_iso()?)
-    }
-
     /// Time in the current time.
     #[staticmethod]
     pub fn now() -> Self {
@@ -139,6 +133,24 @@ impl PyTime {
         self.0.mjd()
     }
 
+    /// Julian Date in UTC scaled time.
+    #[getter]
+    pub fn utc_jd(&self) -> f64 {
+        self.0.utc().jd
+    }
+
+    /// Modified Julian Date in UTC scaled time.
+    #[getter]
+    pub fn utc_mjd(&self) -> f64 {
+        self.0.utc().jd
+    }
+
+    /// Time in the UTC ISO time format.
+    #[getter]
+    pub fn iso(&self) -> PyResult<String> {
+        Ok(self.0.utc().to_iso()?)
+    }
+
     #[staticmethod]
     pub fn j2000() -> Self {
         PyTime(Time::<TDB>::new(2451545.0))