A Planisphere or ‘Star Wheel’ is the perfect way to learn how to recognise the stars and constellations. It consists of a star chart showing all stars and constellations that are visible from a certain area (latitude). However, stars rise and set and the Night Sky changes from season to season. Therefore a second disc is placed on top of the star chart, containing a ‘horizon’ that defines the visible part of the sky at any given moment, which is naturally half of the total starry sky. That moment can be set at the desired date and time.
