Using the compass (and local time and our location) Seestar will find the approximate location of the objects within a few degrees. If it's dark, and Seestar sees enough stars, it will find the object by plate solving.
In the case of Sun and Moon, after finding the approximate position it starts to slew around this position. It moves towards to the brighter side of the field of view, this is how it finds these two objects. And this is why it cannot find the Moon during daylight. And this is why it will never find any objects, when the sky is not dark enough (exept for the Sun).
