The increasing improvement of energy sustainability entails an increase in the use of heliostats in small applications for urban environments. For these applications, smaller heliostats and lower distances traveled by reflected rays are proposed, and, consequently, higher tolerances in error are allowed. This paper describes a new simple heliostatic system suitable for small applications based on a polar heliostat which redirects the sun's rays parallel to the earth polar axis. Additionally, these solar rays can be redirected towards a desired point by means of a fixed secondary mirror. The polar heliostat is composed of a polygon that is deformable due to the rotary movement of axis A-A' parallel to the earth's axis. Its astronomical and mechanical principles are described in the paper. The device is quite simple and it only needs a single action for its positioning, both in elevation and in azimuth, so that it is easily implemented by an electronic controller. Moreover, it is possible to associate and control different heliostats by a single engine. Finally, in this paper, the systematic pointing error of the polar heliostat, and its dependence on the dimensions of the device, has been analyzed, finding out that the average errors decrease as the ratio between the dimensions of the deformable polygon and the thread pitch of axis A-A' increases. Particularly, for the dimensions of the polar heliostat presented, the average pointing error of the device proposed is (epsilon) over bar = 2.96 mrad (with a standard deviation of sigma(epsilon) = 3.11 mrad), which is acceptable for small urban applications. (C) 2015 Elsevier Ltd. All rights reserved.