VenusFixed frame can't be transformed to ICRS

[thandal]

🐞 Problem

I am trying to transform a point on the surface of Venus to the ICRS frame, but it throws an error.

# Point on Venus to IRCS (position and velocity)
v0 = SpheroidLocation(0.0 * au.deg, 0.0 * au.deg, 0.0 * au.m, Venus)
x, y, z = v0.cartesian_cords
# Note: I don't think VenusFixed should really need an obstime, but leaving it blank causes trouble when transforming
# to VenusICRS. Might be a problem.
v_fixed = VenusFixed(obstime=obstime,
                     x=x, y=y, z=z,
                     v_x=0 * au.m / au.s, v_y=0 * au.m / au.s, v_z=0 * au.m / au.s,
                     representation_type='cartesian', differential_type='cartesian')
v_icrs = v_fixed.transform_to(ac.ICRS())

Error:
ConvertError: Cannot transform from <class 'poliastro.frames.fixed.VenusFixed'> to <class 'astropy.coordinates.builtin_frames.icrs.ICRS'>

I have found a workaround however, which is to simply to transform to VenusICRS -- even just instantiating the VenusICRS class once makes it work therafter!?!

## HACK: have to instantiate VenusICRS frame because something is busted?!?
v_vicrs = v_fixed.transform_to(VenusICRS(obstime=obstime))
v_icrs = v_fixed.transform_to(ac.ICRS())

🖥 Please paste the output of following commands

not using conda

• conda info -a (only if you have conda)
• conda list (only if you have conda)
• pip freeze

# Paste your output here:
$ pip freeze
absl-py==1.2.0
aiohttp==3.8.1
aiosignal==1.2.0
alabaster==0.7.12
antlr4-python3-runtime==4.8
anyio==3.6.1
argon2-cffi==21.3.0
argon2-cffi-bindings==21.2.0
astropy==5.1.1
astroquery==0.4.6
asttokens==2.0.5
async-timeout==4.0.2
attrs==20.2.0
Automat==0.8.0
Babel==2.10.3
backcall==0.2.0
beautifulsoup4==4.11.1
binwalk==2.2.0
bleach==5.0.1
blinker==1.4
boto3==1.24.36
botocore==1.27.36
cachetools==5.2.0
certifi==2019.11.28
cffi==1.15.1
chardet==3.0.4
charset-normalizer==2.1.0
Click==7.0
cloud-init==22.4.2
colorama==0.4.3
coloredlogs==15.0.1
command-not-found==0.3
configobj==5.0.6
constantly==15.1.0
cryptography==2.8
cycler==0.11.0
datasets==2.3.2
dbus-python==1.2.16
debugpy==1.6.2
decorator==5.1.1
defusedxml==0.7.1
dill==0.3.5.1
distro==1.4.0
distro-info===0.23ubuntu1
docformatter==1.4
docutils==0.15.2
emoji==2.0.0
entrypoints==0.3
executing==0.8.3
fairscale==0.4.6
fastjsonschema==2.16.1
filelock==3.7.1
flake8==4.0.1
flake8-bugbear==22.7.1
fonttools==4.34.4
frozenlist==1.3.0
fsspec==2022.5.0
gitdb==4.0.9
gitdb2==4.0.2
GitPython==3.1.27
google-api-core==2.8.2
google-auth==2.9.1
google-auth-oauthlib==0.4.6
google-cloud-core==2.3.2
google-cloud-storage==2.4.0
google-crc32c==1.3.0
google-resumable-media==2.3.3
googleapis-common-protos==1.56.4
grpcio==1.47.0
h5py==3.7.0
html5lib==1.1
httplib2==0.14.0
huggingface-hub==0.8.1
humanfriendly==10.0
hydra-core==1.1.2
hyperlink==19.0.0
idna==2.8
imagesize==1.4.1
importlib-metadata==4.2.0
importlib-resources==5.2.3
incremental==16.10.1
iniconfig==1.1.1
iopath==0.1.10
ipykernel==6.15.1
ipython==8.4.0
ipython-genutils==0.2.0
ipywidgets==7.7.1
jedi==0.18.1
Jinja2==3.1.2
jmespath==1.0.1
joblib==1.1.0
jplephem==2.18
json5==0.9.8
jsonlines==3.1.0
jsonpatch==1.22
jsonpointer==2.0
jsonschema==3.2.0
jupyter==1.0.0
jupyter-client==7.3.4
jupyter-console==6.4.4
jupyter-core==4.11.1
jupyter-http-over-ws==0.0.8
jupyter-server==1.18.1
jupyterlab==3.4.3
jupyterlab-pygments==0.2.2
jupyterlab-server==2.15.0
jupyterlab-widgets==1.1.1
keyring==18.0.1
kiwisolver==1.4.4
language-selector==0.1
launchpadlib==1.10.13
lazr.restfulclient==0.14.2
lazr.uri==1.0.3
llvmlite==0.39.1
Markdown==3.3.2
markdown-it-py==0.5.8
MarkupSafe==2.1.1
matplotlib==3.5.2
matplotlib-inline==0.1.3
mccabe==0.6.1
mistune==0.8.4
mock==4.0.3
more-itertools==4.2.0
multidict==6.0.2
multiprocess==0.70.13
myst-parser==0.12.10
nbclassic==0.4.3
nbclient==0.6.6
nbconvert==6.5.0
nbformat==5.4.0
nest-asyncio==1.5.5
netifaces==0.10.4
nltk==3.7
notebook==6.4.12
notebook-shim==0.1.0
numba==0.56.4
numpy==1.21.0
oauthlib==3.1.0
olefile==0.46
omegaconf==2.1.2
packaging==21.3
pandas==1.4.3
pandocfilters==1.5.0
parso==0.8.3
pexpect==4.6.0
pickleshare==0.7.5
Pillow==9.2.0
plotly==5.11.0
pluggy==1.0.0
poliastro==0.17.0
portalocker==2.5.1
prometheus-client==0.14.1
prompt-toolkit==3.0.30
protobuf==3.19.4
psutil==5.9.1
ptyprocess==0.7.0
pure-eval==0.2.2
py==1.11.0
py-gfm==1.0.2
py-rouge==1.1
pyarrow==8.0.0
pyasn1==0.4.2
pyasn1-modules==0.2.1
pycodestyle==2.8.0
pycparser==2.21
pyerfa==2.0.0.1
pyflakes==2.4.0
Pygments==2.12.0
PyGObject==3.36.0
PyHamcrest==1.9.0
PyJWT==1.7.1
pymacaroons==0.13.0
PyNaCl==1.3.0
PyOpenGL==3.1.0
pyOpenSSL==19.0.0
pyparsing==3.0.9
PyQt5==5.14.1
pyqtgraph==0.11.0rc0
pyrsistent==0.15.5
pyserial==3.4
pytest==7.1.2
pytest-datadir==1.3.1
pytest-regressions==2.3.1
python-apt==2.0.0+ubuntu0.20.4.8
python-dateutil==2.8.2
python-debian===0.1.36ubuntu1
pytz==2022.1
pyvo==1.4
PyYAML==5.3.1
pyzmq==23.2.0
qtconsole==5.3.1
QtPy==2.1.0
regex==2022.7.9
requests==2.22.0
requests-mock==1.9.3
requests-oauthlib==1.3.1
requests-unixsocket==0.2.0
responses==0.18.0
rsa==4.9
s3transfer==0.6.0
scikit-learn==1.1.1
scipy==1.8.1
SecretStorage==2.3.1
Send2Trash==1.8.0
service-identity==18.1.0
sh==1.14.3
simplejson==3.16.0
sip==4.19.21
six==1.14.0
smmap==5.0.0
sniffio==1.2.0
snowballstemmer==2.2.0
sos==4.4
soupsieve==2.3.2.post1
Sphinx==2.2.2
sphinx-autodoc-typehints==1.10.3
sphinx-rtd-theme==1.0.0
sphinxcontrib-applehelp==1.0.2
sphinxcontrib-devhelp==1.0.2
sphinxcontrib-htmlhelp==2.0.0
sphinxcontrib-jsmath==1.0.1
sphinxcontrib-qthelp==1.0.3
sphinxcontrib-serializinghtml==1.1.5
ssh-import-id==5.10
stack-data==0.3.0
subword-nmt==0.3.8
systemd-python==234
tenacity==8.1.0
tensorboard==2.9.1
tensorboard-data-server==0.6.1
tensorboard-plugin-wit==1.8.1
tensorboardX==2.5.1
terminado==0.15.0
threadpoolctl==3.1.0
tinycss2==1.1.1
tokenizers==0.12.1
tomli==1.2.3
torch==1.12.0
torchtext==0.13.0
tornado==6.2
tqdm==4.62.3
traitlets==5.3.0
Twisted==18.9.0
typing-extensions==4.3.0
ubuntu-advantage-tools==27.12
ufw==0.36
unattended-upgrades==0.1
Unidecode==1.3.4
untokenize==0.1.1
urllib3==1.25.8
wadllib==1.3.3
wcwidth==0.2.5
webencodings==0.5.1
websocket-client==1.3.3
websocket-server==0.6.4
Werkzeug==2.2.0
widgetsnbextension==3.6.1
xxhash==3.0.0
yarl==1.7.2
zipp==1.0.0
zope.interface==4.7.1

# Paste your output here:

💡 Possible solutions

📋 Steps to solve the problem

• Comment below about what you've started working on.
• Add, commit, push your changes
• Submit a pull request and add this in comments - Addresses #<put issue number here>
• Ask for a review in comments section of pull request
• Celebrate your contribution to this project 🎉