## 3 Results  
### The Performance Insensitivity Threshold of Selected PV Technologies, as a Function of Direction  
The measurement results showed the performance insensitivity thresholds of the m-Si, p-Si and a-Si modules depending on alignment changes. In the case of same-direction changes around the FP the performance deviations were not the same. Figures 8-10 provide information for the easier interpretation of the solar tracking sensors' inaccuracy. Figures 8-10 show no variation as a function of the gap relative to the focus point (FP) for any of the modules if the angle of deviation is below 3\({}^{\circ}\). Indeed, in every direction and for every technology, there is still 100% of performance (pink color) below 3\({}^{\circ}\) of \"offset\" compared to the FP and less than 2% of loss below 5\({}^{\circ}\). The most indifferent orientation was north-south up to 5\({}^{\circ}\). The east and west measurements showed a 1% power reduction in the case of 4.5\({}^{\circ}\)-5\({}^{\circ}\) compared to the FP. The north-west orientation was the most sensitive setting with a 2% performance change in the case of a change in alignment of between 4.5\({}^{\circ}\)and 5\({}^{\circ}\). The average values were the same for all three technologies up to 5\({}^{\circ}\) (Figures 8-10). Up to a deviation of 10\({}^{\circ}\) the m-Si, p-Si and a-Si module data showed a 1-4% change in power. That was the limit where the performance features of the measured technologies were almost the same. Only the p-Si technology differs by 1% in the case of the south-west orientation. In the case of a 20\({}^{\circ}\) change it becomes more visible which orientation causes greater deviation. The least sensitive orientation is south-north, where the crystalline technologies showed 4%, while the a-Si one showed 5% power reduction compared to the FP. In the case of the east-west orientation the values were reduced by 5-8% (Figures 8-10). The measurements performed for inclination changes towards north-west, south-west, south-east, and north-east showed about an 8-12% performance loss for the crystalline modules, while the a-Si module seemed more sensitive with 11-16%. It can be seen that when the solar tracking uncertainty was increased to 20\({}^{\circ}\), the orientation sensitivity of the technologies used became measurable. These features were also observable for a 30\({}^{\circ}\) uncertainty, but the performance change showed a greater difference. In this case, the biggest difference was again seen for the north-west, south-west, south-east, and north-east directions (Figures 8-10). In the cases of solar tracking deviations of 20\({}^{\circ}\) and 30\({}^{\circ}\), it is not only the technology-specific differences that can be seen, but also the fact that the western deviation is 1-5% more sensitive compared to the eastern direction (Figures 8-10). The explanation is not only that the direct and diffuse radiation from the sun changes with the orientation of the module, but there is also an influence by reflected radiation from the surroundings. Our aim was to publish our experimental and theoretical results in as much detail as possible. This method ensures the reproducibility of experimental results for other researchers. These results may make the planning of solar tracking sensor investments easier and help with the estimate calculations of total investment and operational costs and their return concerning monocrystalline, polycrystalline and amorphous silicon photovoltaic systems. The results also provide guidance for the tracking error values of solar tracking sensors. Polynomial Regression Models of Dual-Axis Solar Tracking m-Si, p-Si and a-Si Systems between 0-30\({}^{\circ}\) of Deviation Compared to the FP  
Polynomial regression models (Tables 3-8) have been created from the results of Figures 8-10 by Matlab software. This method ensures the reproducibility of experimental results for other researchers.