Abstract: The present disclosure describes systems and methods for centering a circular object, such as a petri dish, between a plurality of pins. For example, in one embodiment, a method comprises placing a circular object on a rotatable platform surrounded by three moveable pins. In order to roughly center the circular object, the method further comprises moving, for a first time, all of the pins toward the circular object until at least two out of the three pins are touching the circular object. In order to more accurately center the circular object, the method further comprises: moving all of the pins away from the circular object so that it can be rotated without substantial inference; rotating the platform approximately 60 degrees, wherein rotating the platform causes the circular object to also rotate by approximately 60 degrees; and moving, for a second time, all of the pins toward the circular object.