1. a circular star chart that can be adjusted to show which stars are visible at any given time and date
Usage: astronomy
2. a map projection of a sphere or part of a sphere onto a plane
Usage: cartography; technical

Examples

• The astronomy teacher handed out planispheres to help students identify constellations.
• Using a planisphere, we could determine which stars would be visible at midnight.
• The planisphere showed that Orion would be prominent in the winter sky.
• She rotated the planisphere to match the current date and time.
• The cartographer created a planisphere projection of the northern hemisphere.
• Students learned to use their planispheres during the stargazing field trip.