cerridwen 1.0rc1

Moon data library and API server

Cerridwen provides data on the moon that is suitable for both astronomical and astrological purposes. It comes with a simple command-line utility and a JSON server.

The motivation for this package is to have a reliable open-source library and API that provides data on the moon and, eventually, other planetary bodies at a certain point in time.

Contents

• Requirements

• Quickstart

• FAQ

• Licensing

Requirements

Cerridwen depends on Python 3. You might be able to make it work with Python 2 as well. Patches welcome! Please let me know if there’s a version of Python 3 that does not run Cerridwen properly.

It also depends on these packages:

• pyswisseph, the Python interface to the Swiss Ephemeris library

• numpy, which Cerridwen uses for its ephemeris calculations

• Flask, if you wish to run Cerridwen’s API server

Quickstart

$ pip install cerridwen

To test Cerridwen’s data on the console, invoke:

$ cerridwen

If everything is to your satisfaction you can then start the API server:

$ cerridwen-server

It will start up in the foreground and listen on port 2828, serving moon data via HTTP in JSON format at the URI /v1/moon.

You can test it as follows:

$ curl http://localhost:2828/v1/moon

This should give you a proper JSON response with the current moon data.

Change the listen port by passing the -p switch to cerridwen-server, followed by the desired port.

FAQ

What’s the guaranteed precision of the generated data?

For new and full moons (and other angles) the maximum error is smaller than 1/10^6.

What zodiac is used for the longitudes?

All longitudes whether absolute or relative use the tropical zodiac, i.e. zero degrees refers to zero degrees tropical Aries, which in turn corresponds to the sun’s position at the vernal equinox of the year in question.

What about other planetary bodies?

The source code is designed to be easily extensible to other planets and points. The goal is to add more planets once the moon interface is reasonably mature.

Will you add more moon data?

Yes! For example equatorial latitude, lunation number and rise/set times.

How can I help?

First and foremost: use it! Also: tell your friends and fellow astronomers/astrologers!

You can also help write docs, contribute source code and tell me what you’d like to see in the project.

Donations are also welcome.

Licensing

Cerridwen is distributed under the MIT license, as follows.

Copyright (c) 2014 Leslie P. Polzer <[e-mail]>

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.