Learning the Sky

The first step in learning the night sky is to recognize the brighter constellations. The most common of way of learning this is with a simple planisphere; a star chart in the form of two adjustable disks that rotate on a common center. It can be adjusted to display the visible stars for any time and date. Astrolabe which was widely used by old-time astronomers in the history is a predecessor of the modern planisphere.