diff --git a/appveyor.yml b/appveyor.yml
index 89251ed7..59642987 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -20,9 +20,6 @@ branches:
 
 environment:
   matrix:
-    - TOXENV: check
-      PYTHON: C:\Python36\python.exe
-
     - TOXENV: 'py36'
       PYTHON: C:\Python36-x64\python.exe
 
diff --git a/src/poliastro/twobody/orbit.py b/src/poliastro/twobody/orbit.py
index f180587c..9774f990 100644
--- a/src/poliastro/twobody/orbit.py
+++ b/src/poliastro/twobody/orbit.py
@@ -924,27 +924,32 @@ class Orbit(object):
             time_of_flight = time.TimeDelta(value)
 
         cartesian = propagate(self, time_of_flight, method=method, rtol=rtol, **kwargs)
+        new_epoch = self.epoch + time_of_flight
 
+        # TODO: Unify with sample
         # If the frame supports obstime, set the time values
-        kwargs = {}
-        if "obstime" in self.frame.frame_attributes:
-            kwargs["obstime"] = self.epoch + time_of_flight
-        else:
-            warn(
-                "Frame {} does not support 'obstime', time values were not returned".format(
-                    self.frame.__class__
-                )
+        try:
+            kwargs = {}
+            if "obstime" in self.frame.frame_attributes:
+                kwargs["obstime"] = new_epoch
+
+            # Use of a protected method instead of frame.realize_frame
+            # because the latter does not let the user choose the representation type
+            # in one line despite its parameter names, see
+            # https://github.com/astropy/astropy/issues/7784
+            coords = self.frame._replicate(
+                cartesian, representation_type="cartesian", **kwargs
             )
 
-        # Use of a protected method instead of frame.realize_frame
-        # because the latter does not let the user choose the representation type
-        # in one line despite its parameter names, see
-        # https://github.com/astropy/astropy/issues/7784
-        coords = self.frame._replicate(
-            cartesian, representation_type="cartesian", **kwargs
-        )
+            return self.from_coords(self.attractor, coords, plane=self.plane)
 
-        return self.from_coords(self.attractor, coords, plane=self.plane)
+        except NotImplementedError:
+            return self.from_vectors(
+                self.attractor,
+                cartesian.xyz,
+                cartesian.differentials["s"].d_xyz,
+                new_epoch,
+            )
 
     @u.quantity_input(value=u.rad)
     def propagate_to_anomaly(self, value):
diff --git a/tox.ini b/tox.ini
index 20b2af3e..69731452 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,7 +17,7 @@ basepython =
     py35: {env:PYTHON:python3.5}
     {py36,docs}: {env:PYTHON:python3.6}
     py37: {env:PYTHON:python3.7}
-    {clean,check}: {env:PYTHON:python3}
+    {clean,check,reformat}: {env:PYTHON:python3}
 setenv =
     PYTHONPATH={toxinidir}/tests
     PYTHONUNBUFFERED=yes

Cannot propagate orbits around custom bodies
Even after fixing the case of sampling #649, orbits around custom bodies still can't be propagated:

```
>>> from poliastro.twobody import Orbit
>>> from poliastro.bodies import Moon
>>> from astropy import units as u
>>> orb = Orbit.from_vectors(Moon, [-17621.48704193,   9218.72943252, -10947.19144579] * u.km, [ -6985.91793854, -13970.02807282,  -7272.34554685] * u.km / u.day)
>>> orb
2211 x 22792 km x 36.0 deg orbit around Moon (☾) at epoch J2000.000 (TT)
>>> orb.sample(3)
/home/juanlu/Development/poliastro/poliastro-library/src/poliastro/twobody/orbit.py:1082: UserWarning:

No frame found for attractor Moon (☾), returning only cartesian coordinates instead

<CartesianRepresentation (x, y, z) in km
    [(  1738.77087758, -814.03020271,   1096.10391796),
     (-17926.29064628, 8392.44675468, -11300.55584963),
     (  1738.77087758, -814.03020271,   1096.10391796)]
 (has differentials w.r.t.: 's')>
>>> orb.propagate(orb.period / 2)
Traceback (most recent call last):
  File "/home/juanlu/Development/poliastro/poliastro-library/src/poliastro/frames.py", line 337, in get_frame
    frames = _FRAME_MAPPING[attractor]
KeyError: Moon (☾)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/juanlu/Development/poliastro/poliastro-library/src/poliastro/twobody/orbit.py", line 913, in propagate
    if "obstime" in self.frame.frame_attributes:
  File "/home/juanlu/Development/poliastro/poliastro-library/src/poliastro/twobody/orbit.py", line 101, in frame
    self._frame = get_frame(self.attractor, self._plane, self.epoch)
  File "/home/juanlu/Development/poliastro/poliastro-library/src/poliastro/frames.py", line 340, in get_frame
    "Frames for orbits around custom bodies are not yet supported"
NotImplementedError: Frames for orbits around custom bodies are not yet supported
```

To fix this, we should:

1. Add a test, similar to #650, but using `.propagate` instead of `.sample`
2. Try a similar logic to propagate orbits without frames
diff --git a/src/poliastro/tests/tests_twobody/test_propagation.py b/src/poliastro/tests/tests_twobody/test_propagation.py
index f9c07e7f..9ad036aa 100644
--- a/src/poliastro/tests/tests_twobody/test_propagation.py
+++ b/src/poliastro/tests/tests_twobody/test_propagation.py
@@ -329,7 +329,7 @@ def test_propagation_sets_proper_epoch():
     assert propagated.epoch == expected_epoch
 
 
-def test_propagation_custom_body_raises_warning_and_returns_coords():
+def test_sample_custom_body_raises_warning_and_returns_coords():
     # See https://github.com/poliastro/poliastro/issues/649
     orbit = Orbit.circular(Moon, 100 * u.km)
 
@@ -340,3 +340,9 @@ def test_propagation_custom_body_raises_warning_and_returns_coords():
 
     assert isinstance(coords, CartesianRepresentation)
     assert len(coords) == 10
+
+
+def test_propagation_custom_body_works():
+    # See https://github.com/poliastro/poliastro/issues/649
+    orbit = Orbit.circular(Moon, 100 * u.km)
+    orbit.propagate(1 * u.h)

pip install -e .[dev]
parse_log_pytest
pytest
pytest pytest-cov pytest-mpl
3.6
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
alabaster==0.7.13
argon2-cffi==21.3.0
argon2-cffi-bindings==21.2.0
astropy==3.2.3
astroquery==0.4.3
async-generator==1.10
attrs @ file:///opt/conda/conda-bld/attrs_1642510447205/work
Babel==2.11.0
backcall==0.2.0
beautifulsoup4==4.12.3
black==22.8.0
bleach==4.1.0
certifi==2021.5.30
cffi==1.15.1
charset-normalizer==2.0.12
click==8.0.4
comm==0.1.4
coverage==6.2
cryptography==40.0.2
cycler==0.11.0
dataclasses==0.8
decorator==5.1.1
defusedxml==0.7.1
docutils==0.18.1
entrypoints==0.4
html5lib==1.1
idna==3.10
imagesize==1.4.1
importlib-metadata @ file:///tmp/build/80754af9/importlib-metadata_1631916693255/work
importlib-resources==5.4.0
iniconfig @ file:///home/linux1/recipes/ci/iniconfig_1610983019677/work
ipykernel==5.5.6
ipython==7.16.3
ipython-genutils==0.2.0
ipywidgets==7.8.5
isort==5.10.1
jedi==0.17.2
jeepney==0.7.1
Jinja2==3.0.3
jplephem==2.22
jsonschema==3.2.0
jupyter-client==7.1.2
jupyter-core==4.9.2
jupyterlab-pygments==0.1.2
jupyterlab_widgets==1.1.11
keyring==23.4.1
kiwisolver==1.3.1
llvmlite==0.36.0
MarkupSafe==2.0.1
matplotlib==3.3.4
mimeparse==0.1.3
mistune==0.8.4
more-itertools @ file:///tmp/build/80754af9/more-itertools_1637733554872/work
mypy-extensions==1.0.0
nbclient==0.5.9
nbconvert==6.0.7
nbformat==5.1.3
nbsphinx==0.8.8
nest-asyncio==1.6.0
notebook==6.4.10
numba==0.53.1
numpy==1.19.5
packaging @ file:///tmp/build/80754af9/packaging_1637314298585/work
pandas==1.1.5
pandocfilters==1.5.1
parso==0.7.1
pathspec==0.9.0
pexpect==4.9.0
pickleshare==0.7.5
Pillow==8.4.0
platformdirs==2.4.0
plotly==3.10.0
pluggy @ file:///tmp/build/80754af9/pluggy_1615976315926/work
-e git+https://github.com/poliastro/poliastro.git@9264919ae2a37d5e37df72b3a42461e45a9f5535#egg=poliastro
prometheus-client==0.17.1
prompt-toolkit==3.0.36
ptyprocess==0.7.0
py @ file:///opt/conda/conda-bld/py_1644396412707/work
pycodestyle==2.10.0
pycparser==2.21
Pygments==2.14.0
pyparsing @ file:///tmp/build/80754af9/pyparsing_1635766073266/work
pyrsistent==0.18.0
pytest==6.2.4
pytest-cov==2.5.1
pytest-mpl==0.17.0
python-dateutil==2.9.0.post0
pytz==2025.2
pyvo==1.1
pyzmq==25.1.2
requests==2.27.1
retrying==1.3.4
scipy==1.5.4
SecretStorage==3.3.3
Send2Trash==1.8.3
six==1.17.0
snowballstemmer==2.2.0
soupsieve==2.3.2.post1
Sphinx==5.3.0
sphinx-rtd-theme==2.0.0
sphinxcontrib-applehelp==1.0.2
sphinxcontrib-devhelp==1.0.2
sphinxcontrib-htmlhelp==2.0.0
sphinxcontrib-jquery==4.1
sphinxcontrib-jsmath==1.0.1
sphinxcontrib-qthelp==1.0.3
sphinxcontrib-serializinghtml==1.1.5
terminado==0.12.1
testpath==0.6.0
toml @ file:///tmp/build/80754af9/toml_1616166611790/work
tomli==1.2.3
tornado==6.1
traitlets==4.3.3
typed-ast==1.5.5
typing_extensions @ file:///opt/conda/conda-bld/typing_extensions_1647553014482/work
urllib3==1.26.20
wcwidth==0.2.13
webencodings==0.5.1
widgetsnbextension==3.6.10
zipp @ file:///tmp/build/80754af9/zipp_1633618647012/work

name: poliastro
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - attrs=21.4.0=pyhd3eb1b0_0
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2021.5.30=py36h06a4308_0
  - importlib-metadata=4.8.1=py36h06a4308_0
  - importlib_metadata=4.8.1=hd3eb1b0_0
  - iniconfig=1.1.1=pyhd3eb1b0_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.3=he6710b0_2
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - more-itertools=8.12.0=pyhd3eb1b0_0
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - packaging=21.3=pyhd3eb1b0_0
  - pip=21.2.2=py36h06a4308_0
  - pluggy=0.13.1=py36h06a4308_0
  - py=1.11.0=pyhd3eb1b0_0
  - pyparsing=3.0.4=pyhd3eb1b0_0
  - pytest=6.2.4=py36h06a4308_2
  - python=3.6.13=h12debd9_1
  - readline=8.2=h5eee18b_0
  - setuptools=58.0.4=py36h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - toml=0.10.2=pyhd3eb1b0_0
  - typing_extensions=4.1.1=pyh06a4308_0
  - wheel=0.37.1=pyhd3eb1b0_0
  - xz=5.6.4=h5eee18b_1
  - zipp=3.6.0=pyhd3eb1b0_0
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - alabaster==0.7.13
      - argon2-cffi==21.3.0
      - argon2-cffi-bindings==21.2.0
      - astropy==3.2.3
      - astroquery==0.4.3
      - async-generator==1.10
      - babel==2.11.0
      - backcall==0.2.0
      - beautifulsoup4==4.12.3
      - black==22.8.0
      - bleach==4.1.0
      - cffi==1.15.1
      - charset-normalizer==2.0.12
      - click==8.0.4
      - comm==0.1.4
      - coverage==6.2
      - cryptography==40.0.2
      - cycler==0.11.0
      - dataclasses==0.8
      - decorator==5.1.1
      - defusedxml==0.7.1
      - docutils==0.18.1
      - entrypoints==0.4
      - html5lib==1.1
      - idna==3.10
      - imagesize==1.4.1
      - importlib-resources==5.4.0
      - ipykernel==5.5.6
      - ipython==7.16.3
      - ipython-genutils==0.2.0
      - ipywidgets==7.8.5
      - isort==5.10.1
      - jedi==0.17.2
      - jeepney==0.7.1
      - jinja2==3.0.3
      - jplephem==2.22
      - jsonschema==3.2.0
      - jupyter-client==7.1.2
      - jupyter-core==4.9.2
      - jupyterlab-pygments==0.1.2
      - jupyterlab-widgets==1.1.11
      - keyring==23.4.1
      - kiwisolver==1.3.1
      - llvmlite==0.36.0
      - markupsafe==2.0.1
      - matplotlib==3.3.4
      - mimeparse==0.1.3
      - mistune==0.8.4
      - mypy-extensions==1.0.0
      - nbclient==0.5.9
      - nbconvert==6.0.7
      - nbformat==5.1.3
      - nbsphinx==0.8.8
      - nest-asyncio==1.6.0
      - notebook==6.4.10
      - numba==0.53.1
      - numpy==1.19.5
      - pandas==1.1.5
      - pandocfilters==1.5.1
      - parso==0.7.1
      - pathspec==0.9.0
      - pexpect==4.9.0
      - pickleshare==0.7.5
      - pillow==8.4.0
      - platformdirs==2.4.0
      - plotly==3.10.0
      - prometheus-client==0.17.1
      - prompt-toolkit==3.0.36
      - ptyprocess==0.7.0
      - pycodestyle==2.10.0
      - pycparser==2.21
      - pygments==2.14.0
      - pyrsistent==0.18.0
      - pytest-cov==2.5.1
      - pytest-mpl==0.17.0
      - python-dateutil==2.9.0.post0
      - pytz==2025.2
      - pyvo==1.1
      - pyzmq==25.1.2
      - requests==2.27.1
      - retrying==1.3.4
      - scipy==1.5.4
      - secretstorage==3.3.3
      - send2trash==1.8.3
      - six==1.17.0
      - snowballstemmer==2.2.0
      - soupsieve==2.3.2.post1
      - sphinx==5.3.0
      - sphinx-rtd-theme==2.0.0
      - sphinxcontrib-applehelp==1.0.2
      - sphinxcontrib-devhelp==1.0.2
      - sphinxcontrib-htmlhelp==2.0.0
      - sphinxcontrib-jquery==4.1
      - sphinxcontrib-jsmath==1.0.1
      - sphinxcontrib-qthelp==1.0.3
      - sphinxcontrib-serializinghtml==1.1.5
      - terminado==0.12.1
      - testpath==0.6.0
      - tomli==1.2.3
      - tornado==6.1
      - traitlets==4.3.3
      - typed-ast==1.5.5
      - urllib3==1.26.20
      - wcwidth==0.2.13
      - webencodings==0.5.1
      - widgetsnbextension==3.6.10
prefix: /opt/conda/envs/poliastro

src/poliastro/tests/tests_twobody/test_propagation.py::test_propagation_custom_body_works
src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[0.0] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[0.5] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[0.99] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[0.995] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[0.999] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[0.9999] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[1.00001] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[1.0001] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[1.001] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[1.005] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[1.01] src/poliastro/tests/tests_twobody/test_propagation.py::test_mean_motion[2.0] src/poliastro/tests/tests_twobody/test_propagation.py::test_propagation[kepler] src/poliastro/tests/tests_twobody/test_propagation.py::test_propagation[mean_motion] src/poliastro/tests/tests_twobody/test_propagation.py::test_propagation[cowell] src/poliastro/tests/tests_twobody/test_propagation.py::test_propagating_to_certain_nu_is_correct src/poliastro/tests/tests_twobody/test_propagation.py::test_propagate_accepts_timedelta src/poliastro/tests/tests_twobody/test_propagation.py::test_propagation_hyperbolic src/poliastro/tests/tests_twobody/test_propagation.py::test_propagation_mean_motion_parabolic src/poliastro/tests/tests_twobody/test_propagation.py::test_propagation_zero_time_returns_same_state src/poliastro/tests/tests_twobody/test_propagation.py::test_propagation_hyperbolic_zero_time_returns_same_state src/poliastro/tests/tests_twobody/test_propagation.py::test_apply_zero_maneuver_returns_equal_state src/poliastro/tests/tests_twobody/test_propagation.py::test_cowell_propagation_with_zero_acceleration_equals_kepler src/poliastro/tests/tests_twobody/test_propagation.py::test_cowell_propagation_circle_to_circle src/poliastro/tests/tests_twobody/test_propagation.py::test_propagate_to_date_has_proper_epoch src/poliastro/tests/tests_twobody/test_propagation.py::test_propagate_long_times_keeps_geometry[mean_motion] src/poliastro/tests/tests_twobody/test_propagation.py::test_long_propagations_kepler_agrees_mean_motion src/poliastro/tests/tests_twobody/test_propagation.py::test_long_propagation_preserves_orbit_elements[mean_motion] src/poliastro/tests/tests_twobody/test_propagation.py::test_long_propagation_preserves_orbit_elements[kepler] src/poliastro/tests/tests_twobody/test_propagation.py::test_propagation_sets_proper_epoch src/poliastro/tests/tests_twobody/test_propagation.py::test_sample_custom_body_raises_warning_and_returns_coords
appveyor.yml tox.ini src/poliastro/twobody/orbit.py
appveyor.yml tox.ini src/poliastro/twobody/orbit.py