In astronomy, a planisphere is a star chart analog computing instrument in the form of two adjustable disks that rotate on a common pivot. It can be adjusted to display the visible stars for any time and date. It is an instrument to assist in learning how to recognize stars and constellations.
Uncle Al’s Star Wheels are inexpensive star maps, adjustable for any time of night in any month of the year. Print out and build your own “star wheel” to tell the time by the position of three easy to spot constellations! Sure, you could do this with a smart phone app, but — where’s the fun in that? Have your kids build and learn to use something that will make them think. A great “hands on” Astronomy project!