Is it already possible to control two cameras at once?
In the current project, I would need to control a Starlight Xpress and a Canon DSLR simultaneously.
In fact, both should have the same exposure duration and would ideally start exposing synchronously.
If possible I would like to have a checkbox so the DSLR camera operates like a slave of the starlight and exposes as the other does.
If it doesn't exist yet:
How could it be implemented and where would I start?
It's not easy to synchronize multiple cameras (if you do them for 2, you might as well support N cameras). A lot of logic inside Ekos assume single primary camera and single guide camera...etc which is what is used in most amateur setups.
So if you're willing to work on this feature, that would be awesome! but it's going to take quite a bit of work to get done.