This is a functional planisphere coin which you can actually use to locate constellations.
Planispheres are maps of the celestial stars as seen from earth. They are the replacement for the planispheric astrolabe. The first star chart to be called a planisphere was created in 1624. Planispheres are great for learning the constellations and knowing the exact position of the stars at a particular time to get more accurate readings when used with other navigational tools such as the quadrant, nocturnal, astrolabe, back staff and sextant.
One disadvantage of translating stars from an actual spherical view to a flat disk is the distortion caused to the constallations towards the edge of the disk. It causes the images towards the edge of the disk to become stretched out. However, with some practice you will become a pro with this device in no time and be able to compensate for this distortion.
Normally, planispheres consist of several disks which map the stars as viewed from different latitudes and for different seasons. The planisphere geocoins we have made do not have interchangeable disks; however, they still give you a good idea of where the stars are at any time of day, and provide you with a pocket sized tool to help learn the constallations. Its 3.25" diameter size makes it portable, and being made out of metal makes it very durable.
Both Northern Hemisphere and Southern Hemisphere versions are available.
- 3.25" diameter
- Soft enamel color with printing
- Has a spinning disk showing most constellations
- Trackable on Geocaching.com
- Has its own icon that will show in your geocaching profile when you log a find: