From pinhole imaging to planetary orbit: A year-long solar angular measurement with a pinhole camera

We present a year-long experiment using a pinhole camera to determine the Sun's angular size, employing a flat mirror to project large-scale solar images of about 50–60 cm in diameter. Our analysis resolves the annual angular variation of 65 arc sec, reflecting Earth's elliptical orbit. Additionally, we observed atmospheric seeing effects (the effects of atmospheric turbulence) and sunspots visible with the naked eye. The project offers an accessible platform for high school and undergraduate students to engage in scientific inquiry.