Would be nice if the app sent out the aiming error instead of just the satellite's azimuth and elevation.
In essence this would allow to slap the phone onto a DIY rotator and not have to rely on the rotator knowing its own orientation.
The phone could send out a +- 180 azimuth and +-90 elevation as commands to the rotator to tell it the adjustments it needs to make to aim at the satellite. For example a -65, 20 would denote that the satellite is 65 degrees to the left and 20 degrees up. The DIY rotator would only need to control a couple of servos, simplifying the solution by a whole heap.