Albert Y. Shih

@dstansby: That suggestion in specific would have trouble distinguishing between a package that isn't installed in `site-packages` (i.e., via `pip -e`) and actual user code. Of course, one could argue...

@Cadair: What if a user's primarily uses sunpy by running Python scripts in a non-interactive way?

As an aside, what logic is there for DeprecationWarning? I thought they are ignored by default, and then some environments choose to expose them?

Sure, we could add special support for `TimeDelta`, but it might be better to go for an upstream fix for `QuantityAttribute` (and maybe use duck-typing!). Regardless, if your `TimeDelta` is...

Bleh, these values in the SXT header ought to be equal: ``` SOLAR_B0= 3.06603 HGLT_OBS= 0.00000 ``` `HGLT_OBS` is clearly incorrect. We'll need to override `._supported_observer_coordinates()`.

Something like this: ```python @property def _supported_observer_coordinates(self): return [(('hgln_obs', 'solar_b0', 'dsun_obs'), {'lon': self.meta.get('hgln_obs'), 'lat': self.meta.get('solar_b0'), 'radius': self.meta.get('dsun_obs'), 'unit': (u.deg, u.deg, u.m), 'frame': "heliographic_stonyhurst"})] + super()._supported_observer_coordinates ```

I think you'll want to propose adding it to [`astropy/coordinates/tests/helper.py`](https://github.com/astropy/astropy/blob/main/astropy/coordinates/tests/helper.py)

I mean, I wouldn't stake my first-born on it, but I'm pretty sure, yes.

This guide is looking fairly good, but it isn't really structured like a "cheat sheet", so I wouldn't call it that. > > Another possible step to add is deleting...

Interesting – particularly the option to return an optimally rotated rectangle – but as written it relies on the assumption that the corners alone are enough to determine the transformed...