All of the software which drives the calculations on this site is original work, based upon several software packages released under the GNU GPL. Without open source communities, this website would not be possible. All original work is released under version 1 of the GNU GPL. This means that it is free of charge and can be distributed freely. There are only two major restrictions. This information, having been released under the GPL, cannot be sold under any circumstance. Also, when it is redistributed, you must give credit to whom produced it; in this case, the Twelve Star Almanac project. As long as you comply with these terms, the information can be used, changed, stored, transferred, and so forth as you see fit.

The Swiss Ephemeris is used as the main repository and calculator of this site. All information that you see is what my programs made out of the information from the Swiss Ephemeris. My programs provide a much wider range of information, but all of it derived from calculations that are based on what comes out of the Swiss Ephemeris binary, version 1.7.4. This version of the Swiss Ephemeris was released under the GNU GPL version 2+ before 2010. The original work was done in Fortran by NASA's JPL and was later converted to a C-based program and expanded into the Swiss Ephemeris. This program functions as the backbone of the site and is greatly appreciated.

This site uses two information conversion programs, wkhtmltoimage and wkhtmltopdf, to construct pdf files for download. Both packages have been released under GNU GPL version 3+ as of 2010. Use of these programs increases the end product quality attainable compared to similar packages, though they have their own quirks. Despite all of the bugs to work out, I'm pleased with the print quality available from the generated pdf.

Many of the astrological calculations used on this site were inspired by Llewellyn George. His work formed the basis for the methods of calculation implemented here, though some things have been expanded or modified. His book on astrology (a 1984 edition) was my first deep introduction to astrological calculation and interpretation. There are many astrological calculations presented that have nothing to do with Mr. George, but I feel that he is worthy of mention here. Most other information was gathered from the work of many people and confirmed based on the work of reputable astrologers. Some errors may remain, but they should all be minimal.