A planisphere is a must-have device for people who love to stargaze at night. This is a representation of the celestial sphere on a flat plane that can be adjusted around a common pivot to show which stars would be visible in the night sky at any given time and date. This is an especially valuable companion for people who would like to familiarize themselves with the stars and constellations.
The constant movement of the earth causes the appearance of the sky to vary based on the time of the day, at certain times of the year and your specific location on earth. In order to pinpoint the exact location of a star or constellation, you will need to put all these components in consideration. The planisphere will help you do just that.
A planisphere is a circular star chart with an adjustable circular overlay on top of it that has a clear elliptical hole showing the portion of the sky that is visible in a particular location at a given time. With just a simple twist, this device will show you the astronomical sights you can possibly see on your night sky at a particular hour of the day.
There are, however, some complications to the use of a planisphere. Northern and southern hemispheres have different designs of planispheres so if one that has been made for use in the northern hemisphere is used in the southern hemisphere, it may not give you an accurate data. Some models also only work efficiently for a particular range of latitudes, so you have to make sure you get the one is appropriate for your location.