We present a set of exercises and activities, designed for Basic Astronomy disciplines and inspired by Ausubel's multi-contextual approach, relating the limit magnitude concept to the light catching power of an optical instrument. These exercises are compared with stars count , through naked-eye observations, or those made with the aid of optical instruments, and through the use of star charts software. Meanwhile, the student has the opportunity to become familiarized with the sky, binocu lars and telescopes, as well as with several types of software. It is also dis cussed the relation of the stars count with the spatial distribution of these objects and their application in teaching/learning circumstances.
Astronomy; teaching; magnitude