A planisphere is a star chart analog computing instrument in the form of two adjustable disks that rotate on a common pivot. It can be adjusted to display the visible stars for any time and date. It is an instrument to assist in learning how to recognize stars and constellations.
The main disadvantage of this tool is a dependence on the latitude. If it is designed for the particular one, it works properly only in the small range of latitudes around. The planisphere can be bought at most bookstores, but very often just for the local latitude. If you are from north or central Europe and plan to spend holidays in southern Europe, this one cannot be simply used there.
The basic idea was to create a handy utility allowing you to set the desired latitude, display the appropriate sky area on your monitor, and, of course, print it out.
The first version was released in 2003 as a Windows desktop application. As a user base was growing, it was clear that limited language support and platform dependence limit its usage. The complete rewriting was inevitable, but it was a recent advent of internet applications and continuous adoption of novel technologies in major browsers what finally showed the way to go.
The planisphere is now provided as an SVG based web application. No installation, no platform dependence any more. Chinese or Japanese is not an issue any more. Visual appearance of both screen and printed outputs can be easily changed.
There are still several known issues in major browsers but I hope this will improve in a near future.
Feel free to try out this web application!