add note on tomo centering

README.md

@@ -63,7 +63,7 @@ and particle data in the following formats:
 - Relion `.star`
 - Dynamo `.tbl`
 - Cryolo `.cbox` and `.box`
-- EMAN2 `.json`
+- EMAN2 `.json`[^1]
 
 Writer functions currently exist for:
 - `.mrc`
@@ -72,6 +72,8 @@ Writer functions currently exist for:
 - Relion `.star`
 - Dynamo `.tbl`
 
+[^1]: EMAN2 uses the center of the tomogram as the origin for particle coordinates. This means that when opening a tomogram, you'll have to recenter the particles based on its dimensions. To do so automatically, you can use the `center_on_tomo` argument to provide the `hdf` file with the tomogram you want to use.
+
 ## Image data
 
 When possible (and unless disabled), cryohub loads images lazily using [`dask`](https://docs.dask.org/en/stable/array.html). The resulting objects can be treated as normal numpy array, except one needs to call `array.compute()` to apply any pending operations and return the result.