About the developer

prema

Astrologer / developer of Horoscho Chart (Tokyo, Japan)

I have been researching Western astrology for thirty years. For a long time I practised alongside other work; today research, teaching and personal consultations are my full-time profession.

Horoscho Chart grew out of my own daily practice. I wanted a tool that brought astronomy-grade precision and the techniques a working astrologer actually uses together in one place.

The other origin is the idea of learning in your mother tongue. When I began my research there were introductory books in Japanese, but very few serious, specialist works, so I kept taking the long detour of understanding everything in English first and then translating it back into my own words. I want people born outside the English-speaking world to have the chance to learn and read in their own language. That is why Horoscho Chart runs in seven languages.

About this app

Horoscho Chart is not open source. It is developed by one person, but bug reports are very welcome and will be dealt with as quickly as possible. Development continues, and users' feedback shapes what comes next.

Credits and open-source licenses

Horoscho Chart uses the following open-source software.

Skyfield

Astronomical calculations are powered by the Skyfield library. The full text of its license (MIT) follows.

Copyright © 2013–2018 Brandon Rhodes and available under the MIT license:

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Ephemeris data

Planetary and lunar positions are computed from the ephemeris data (DE440 / DE441) published by NASA's Jet Propulsion Laboratory (JPL).

Trademarks and independence

Horoscho Chart is an independent application. It is not affiliated with, endorsed by, or sponsored by the Skyfield project or its author, nor by NASA / JPL. "Skyfield" and all other names are the property of their respective owners. We use these open-source tools and publicly available data with gratitude and respect for their authors and communities.