Thank you Alexey for that answer, but it's not really what I want to do. But your script is a good example that I will keep. In fact, I'd like to keep the camera trajectory in the same order as you do, but always pointing the object at the center, i.e. with orientation quaternions pointing at the object center (0,0,0).
Incidentally, I sent you a message on the support email on another subject.
Best regards,