Estimating star distances with a light bulb

Abstract

Abstract A practical experiment is described to estimate the distance to a star using simple equipment, suitable for secondary or undergraduate students. The brightness of the star is visually matched to a miniature filament lamp, and its distance inferred from the inverse square law. Students gain an appreciation of astronomical units and practice in manipulating powers of 10. By additionally applying knowledge of the H-R diagram and black body radiation, accuracy can be improved to one order of magnitude.