What is a Planisphere and how do I use it?
With a planisphere, or star wheel, you turn a disk to set your time against your date. The edge of the star map then represents the horizon all around you at that time. Some planispheres come with extra features. The most important aspect of a planisphere, however, is the clarity and realism of its star map. Among the many devices on the market, The Night Sky takes the prize in this regard, and features star maps on both sides, one minimizing distortion in the north and the other in the south.
