An improved gnomon

Abstract

During a project work done by a group of students at senior secondary stage with the guidance of the author, the vertical pillar kind of gnomon has been improved upon. Whereas the traditional gnomon can measure altitude of the Sun with a pricision of about 0.25 degree, the improved one can measure it with a precision of about 0.05 degree, by the observation of its shadow only. It also enables in toto to make the plane surface on which it is placed accurately horizontal.