This is a modern recreation of an ancient instrument used to tell the time at night, before there were reliable clocks. You use the positions of the stars to tell the time.
It is made from three layers of laser cut acrylic, each 1/16" thick. They are bound together by a hollow grommet; it is necessary to look through the middle of the instrument in order to make your sightings of the stars.
Full instructions for use can be found here: http://wavytail.com/nocturnal/
Northern hemisphere only - sorry, Antipodeans - you don't have a southern equivalent to the North Star, and are therefore unable to sight the South Pole with a device such as this.
