Your Sky is a Web-based interactive resource available on the Fourmilab since 1998 which makes custom maps of the sky for any location on Earth and any date from 4713 B.C. into the distant future. Maps can include stars as faint as magnitude 6.5, constellation names, outlines, and boundaries, the Moon and planets, deep sky objects from a database of more than 500, and a comet or asteroid whose position is calculated from its orbital elements. A variety of display options allow customising the map for its intended use. All-sky maps or horizon views can be generated, as well as images from a āvirtual telescopeā aimed anywhere in the sky.
Your Sky is implemented as a series of Web pages through which custom sky maps are requested and three Common Gateway Interface (CGI) programs written in C which generate the maps and return them to requesters. The GitHub repository contains all of the Web pages, source code for the CGI programs, images and databases used to generate sky maps, and utilities which automatically update orbital elements of asteroids and comets from databases published by the Jet Propulsion Laboratory. The repository contains everything required to set up your own Your Sky server and may serve as a ācode mineā for development of astronomical applications.