This project hosts various plugins for the OpenCPN chart plotter, which are not bundled with the core package.
OpenCPN is a free software (GPLv2) project to create a concise chart plotter and navigation software, for use underway or as a planning tool. OpenCPN is developed by a team of active sailors using real world conditions for program testing and refinement.
PP3 creates celestialcharts. It generates resolution independent sky maps of very high graphical quality. They can be used for example as illustrations in books or on web pages. Databases are included but you may use own data if you wish.