Handheld Augmented Reality relies on the registration of digital content on physical objects. Yet, the accuracy of this registration depends on environmental conditions. It is therefore important to study the impact of registration jitter on interaction and in particular on pointing at augmented objects where precision may be required. We present an experiment that compares the effect of registration jitter on the following two pointing techniques: (1) screen-centered crosshair pointing; and (2) relative pointing with a cursor bound to the physical object's frame of reference and controlled by indirect relative touch strokes on the screen. The experiment considered both tablet and smartphone form factors. Results indicate that relative pointing in the frame of the physical object is less error prone and is less subject to registration jitter than screencentered crosshair pointing.