The point is that a slaved instance just needs to be able to receive a message: 'go here' or 'change fov to X'. You do not need to make a multi-window version of ESASky, you let the browser itself provide the application contexts.
If the message interface is sufficient open, it might not even need to be an ESASky instance (or EuclidSky) sending the messages; it could be a python notebook.
The point is that a slaved instance just needs to be able to receive a message: 'go here' or 'change fov to X'. You do not need to make a multi-window version of ESASky, you let the browser itself provide the application contexts.
If the message interface is sufficient open, it might not even need to be an ESASky instance (or EuclidSky) sending the messages; it could be a python notebook.