From the angle of geometry to angles in the sky. Obstacles for the conceptualization of astronomical coordinates.

Abstract

In this paper we report on a discussion about learning difficulties related to the definition and measurement of angles in physical (3D) space, on the celestial sphere. We discuss, in particular, the characteristics of the Azimuth and Altitude coordinates necessary for determinig, and the didactical and conceptual difficulties associated with their determination. We also analyse data obtained from personal interviews, group classes and personal drawings made by students from Argentina and Italy, of varied ages: 15-17 years old and adults from the university and future teachers.