My goal is to find a quaternion, that describes the rotation from an initial orientation (given by a quaternion) to a desired 3D point. The following image shows the set-up:
The red camera shows the initial orientation qRed = [1 0 0 0], the blue sphere is at position p = [2 3 1] and the blue camera is supposed to be oriented such that it faces the blue sphere.
How can I find the quaternion qBlue in such a setup?