Journal of Electronics and Informatics
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How to Cite
M., Rajalingam, Krishnasamy P., Ravindra B., Sagayanathan K., and Madan Mohan Kemkar P. 2026. “Design, Implementation, and Experimental Validation of a Low-Cost Autonomous Coelostat System for High-Stability White-Light Solar Imaging”. Journal of Electronics and Informatics 8 (3): 287-300. https://doi.org/10.36548/jei.2026.3.007.
Keywords
Coelostat
Solar Tracking
Solar Position Algorithm
White-Light Solar Imaging
Embedded Control Systems
Instrumentation
Abstract
This research work presents the design, implementation, and experimental testing of a low-cost autonomous coelostat. The coelostat uses a two-mirror system to keep the reflected sunbeam in a fixed position, while compensating for the Sun’s apparent motion in the sky. The coelostat control system is realized using a dsPIC33FJ128GP802 microcontroller in combination with a Raspberry Pi computer-based user interface, implementing an open-loop predictive tracking algorithm based on the NREL Solar Position Algorithm (SPA). With the introduction of the proposed design, there is no need for moving telescopes or optical sensors for feedback, therefore, the mechanical complexity and alignment of the optical components can be reduced significantly. A prototype of the coelostat with three gear-reduced axes of stepper motors (1:410) was developed and tested outdoors. A maximum beam displacement of less than 1 mm at a 3 m projection distance was observed, resulting in a tracking accuracy of 0.5–1.0 arcmin. These results prove that the proposed coelostat is compact, reliable, and affordable instrument for solar white light imaging and spectroscopy as well as educational applications.References
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