A Planisphere can be defined as an astronomical instrument which is used to display the location of stars. The term Planisphere has been derived from the Latin word planisphaerium. This instrument is mostly used by star gazers to help them understand the mechanics of the sky at night. Basically, it is a representation of the celestial sphere on a flat plane that can be adjusted around a common pivot.
It shows which stars would be visible in the night sky at any specific date and time. It can be designed with the polar azimuthal equidistant projection method or the stereographic projection.
Quick Facts: –
- The design of a Planisphere can be different on the basis of its location. They are designed differently for Northern and Southern Hemisphere.
- More accurate ones can represent the declination and right ascension celestial coordinates.
- NASA has a set of Planispheres that are known as Star Wheels or the Kepler Star Wheels.
- This instrument also helps to learn how to recognize different stars and constellations.
- Distortion will always be there while using a Planisphere because it represents the celestial sphere as a flat.
- This instrument can be made at home by printing out the discs and assembling them.
- Some models are designed to work in a specific latitude range.
- The constant movement of the earth causes the appearance of the sky to vary based on the time of the day.
- This circular star chart with an adjustable circular overlay on the very top. This overlay has a clear elliptical hole which shows the portion of the sky that is visible in a particular location.