NOVELTY - The wind resistant celestial tracking apparatus comprises a support structure (20) having a first center of mass mounted on a surface (26) at contact surfaces (27), a tracking assembly (22) having a second center of mass and pivotally coupled to the support structure about a first axis, a payload assembly (24) mounted on the tracking assembly and comprising a third center of mass, where one function of the payload assembly interacts with an electromagnetic radiation, and a contact region of which the boundary circumscribes the contact surfaces, is convex in shape and has a minimum total area.    USE - The wind resistant celestial tracking apparatus is useful in two axis solar energy collection systems.    ADVANTAGE - The celestial tracking apparatus is capable of resisting overturning forces due to wind in part through gravitational forces acting on the moving elements of the structure thus eliminating the need for a massive ballasted or dug-in foundation and potentially reducing the total cost of installation.    DETAILED DESCRIPTION - The wind resistant celestial tracking apparatus comprises a support structure (20) having a first center of mass mounted on a surface (26) at contact surfaces (27), a tracking assembly (22) having a second center of mass and pivotally coupled to the support structure about a first axis, a payload assembly (24) mounted on the tracking assembly and comprising a third center of mass, where one function of the payload assembly interacts with an electromagnetic radiation, a contact region of which the boundary circumscribes the contact surfaces, is convex in shape and has a minimum total area, an overturning axis coincident with points along the boundary of the contact region and not passing through the contact region, a net wind moment resulting from a wind pressure profile acting on the apparatus about the overturning axis, a net gravitational moment resulting from gravitational forces acting on the first, second and third center of masses about the overturning axis, and a net overturning moment maximized about the overturning axis in a direction acting to overturn the apparatus and resulting from a combination of the net wind moment and the net gravitational moment. The magnitude of the net gravitational moment is greater than the magnitude of the net wind moment. The magnitude of a net contribution to the net gravitational moment from the second center of mass and the third center of mass is greater than the magnitude of a contribution from the first center of mass. The payload assembly is an array of photovoltaic modules, an array of concentrating photovoltaic modules, an array of reflective surfaces, or an array of reflective surfaces and an energy collection device. The tracking assembly further comprises a first structure pivotally coupled to the support structure about the first axis, and a second structure pivotally coupled about a second axis. The first axis is vertical or horizontal. The second axis is horizontal or perpendicular to the first axis. The payload assembly is mounted upon the first structure. The self curing compound comprises reinforced concrete.    DESCRIPTION OF DRAWING(S) - The diagram shows a rear perspective view of two axis tracking apparatus.    Support structure (20)    Tracking assembly (22)    Payload assembly (24)    Surface (26)    Contact surface. (27)