from the updated documentation:
... once a plate-solved image is available in Astroart, the rotator can be controlled also for the Star atlas: right-click for the context menu and click "Rotator". A new panel with two arrows and a further menu will be available:
Use the arrow buttons to prepare the rotation, a dotted rectangle will be shown, then click Move rotator.
Other commands:
Angle from North. A rotation will be prepared to align the camera with the equatorial coordinates.
Angle from image... Before using this command open another image from another night: a rotation will be prepared to match the same orientation.
Clear skies, Fabio