kerykeion

Kerykeion

 

Kerykeion is a Python library for astrology. It computes planetary and house positions, detects aspects, and generates SVG charts—including birth, synastry, transit, and composite charts. You can also customize which planets to include in your calculations.

The main goal of this project is to offer a clean, data-driven approach to astrology, making it accessible and programmable.

Kerykeion also integrates seamlessly with LLM and AI applications.

Here is an example of a birthchart:

Web API

If you want to use Kerykeion in a web application, you can try the dedicated web API:

AstrologerAPI

It is open source and directly supports this project.

Donate

Maintaining this project requires substantial time and effort. The Astrologer API alone cannot cover the costs of full-time development. If you find Kerykeion valuable and would like to support further development, please consider donating:

Table of Contents

• Installation
• Basic Usage
• Generate a SVG Chart
  • Birth Chart
  • Synastry Chart
  • Transit Chart
  • Composite Chart
  • Change the Output Directory
  • Change Language
• Report
• Example: Retrieving Aspects
• Ayanamsa (Sidereal Modes)
• House Systems
• Perspective Type
• Themes
• Alternative Initialization
• Lunar Nodes (Rahu & Ketu)
• JSON Support
• Auto Generated Documentation
• Development
• Integrating Kerykeion into Your Project
• License
• Contributing
• Citations

Installation

Kerykeion requires Python 3.9 or higher.

pip3 install kerykeion

Basic Usage

Below is a simple example illustrating the creation of an astrological subject and retrieving astrological details:

from kerykeion import AstrologicalSubject

# Create an instance of the AstrologicalSubject class.
# Arguments: Name, year, month, day, hour, minutes, city, nation
kanye = AstrologicalSubject("Kanye", 1977, 6, 8, 8, 45, "Atlanta", "US")

# Retrieve information about the Sun:
kanye.sun
# > {'name': 'Sun', 'quality': 'Mutable', 'element': 'Air', 'sign': 'Gem', 'sign_num': 2, ...}

# Retrieve information about the first house:
kanye.first_house
# > {'name': 'First_House', 'quality': 'Cardinal', 'element': 'Water', 'sign': 'Can', ...}

# Retrieve the element of the Moon sign:
kanye.moon.element
# > 'Water'

To avoid using GeoNames online, specify longitude, latitude, and timezone instead of city and nation:

kanye = AstrologicalSubject(
    "Kanye", 1977, 6, 8, 8, 45,
    lng=50,
    lat=50,
    tz_str="Europe/Rome",
    city="Rome"
)

Generate a SVG Chart

Birth Chart

from kerykeion import AstrologicalSubject, KerykeionChartSVG

birth_chart = AstrologicalSubject("Kanye", 1977, 6, 8, 8, 45, "Atlanta", "US")
birth_chart_svg = KerykeionChartSVG(birth_chart)
birth_chart_svg.makeSVG()

The SVG file will be saved in the home directory.

Synastry Chart

from kerykeion import AstrologicalSubject, KerykeionChartSVG

first = AstrologicalSubject("John Lennon", 1940, 10, 9, 18, 30, "Liverpool", "GB")
second = AstrologicalSubject("Paul McCartney", 1942, 6, 18, 15, 30, "Liverpool", "GB")

synastry_chart = KerykeionChartSVG(first, "Synastry", second)
synastry_chart.makeSVG()

Transit Chart

from kerykeion import AstrologicalSubject

transit = AstrologicalSubject("Transit", 2025, 6, 8, 8, 45, "Atlanta", "US")
subject = AstrologicalSubject("John Lennon", 1940, 10, 9, 18, 30, "Liverpool", "GB")

transit_chart = KerykeionChartSVG(subject, "Transit", transit)
transit_chart.makeSVG()

Composite Chart

from kerykeion import CompositeSubjectFactory, AstrologicalSubject, KerykeionChartSVG

angelina = AstrologicalSubject("Angelina Jolie", 1975, 6, 4, 9, 9, "Los Angeles", "US", lng=-118.15, lat=34.03, tz_str="America/Los_Angeles")

brad = AstrologicalSubject("Brad Pitt", 1963, 12, 18, 6, 31, "Shawnee", "US", lng=-96.56, lat=35.20, tz_str="America/Chicago")

factory = CompositeSubjectFactory(angelina, brad)
composite_model = factory.get_midpoint_composite_subject_model()

composite_chart = KerykeionChartSVG(composite_model, "Composite")
composite_chart.makeSVG()

Change the Output Directory

To save the SVG file in a custom location, specify new_output_directory:

from kerykeion import AstrologicalSubject, KerykeionChartSVG

first = AstrologicalSubject("John Lennon", 1940, 10, 9, 18, 30, "Liverpool", "GB")
second = AstrologicalSubject("Paul McCartney", 1942, 6, 18, 15, 30, "Liverpool", "GB")

synastry_chart = KerykeionChartSVG(
    first, "Synastry", second,
    new_output_directory="."
)
synastry_chart.makeSVG()

Change Language

You can switch chart language by passing chart_language to the AstrologicalSubject or KerykeionChartSVG classes:

first = AstrologicalSubject("John Lennon", 1940, 10, 9, 18, 30, "Liverpool", "GB", chart_language="ES")

More details here.

Report

from kerykeion import Report, AstrologicalSubject

kanye = AstrologicalSubject("Kanye", 1977, 6, 8, 8, 45, "Atlanta", "US")
report = Report(kanye)
report.print_report()

Returns:

+- Kerykeion report for Kanye -+
+----------+------+-------------+-----------+----------+
| Date     | Time | Location    | Longitude | Latitude |
+----------+------+-------------+-----------+----------+
| 8/6/1977 | 8:45 | Atlanta, US | -84.38798 | 33.749   |
+----------+------+-------------+-----------+----------+
+-----------------+------+-------+------+----------------+
| Planet          | Sign | Pos.  | Ret. | House          |
+-----------------+------+-------+------+----------------+
| Sun             | Gem  | 17.6  | -    | Twelfth_House  |
| Moon            | Pis  | 16.43 | -    | Ninth_House    |
| Mercury         | Tau  | 26.29 | -    | Eleventh_House |
| Venus           | Tau  | 2.03  | -    | Tenth_House    |
| Mars            | Tau  | 1.79  | -    | Tenth_House    |
| Jupiter         | Gem  | 14.61 | -    | Eleventh_House |
| Saturn          | Leo  | 12.8  | -    | Second_House   |
| Uranus          | Sco  | 8.27  | R    | Fourth_House   |
| Neptune         | Sag  | 14.69 | R    | Fifth_House    |
| Pluto           | Lib  | 11.45 | R    | Fourth_House   |
| Mean_Node       | Lib  | 21.49 | R    | Fourth_House   |
| True_Node       | Lib  | 22.82 | R    | Fourth_House   |
| Mean_South_Node | Ari  | 21.49 | R    | Tenth_House    |
| True_South_Node | Ari  | 22.82 | R    | Tenth_House    |
| Chiron          | Tau  | 4.17  | -    | Tenth_House    |
+-----------------+------+-------+------+----------------+
+----------------+------+----------+
| House          | Sign | Position |
+----------------+------+----------+
| First_House    | Can  | 18.0     |
| Second_House   | Leo  | 9.51     |
| Third_House    | Vir  | 4.02     |
| Fourth_House   | Lib  | 3.98     |
| Fifth_House    | Sco  | 9.39     |
| Sixth_House    | Sag  | 15.68    |
| Seventh_House  | Cap  | 18.0     |
| Eighth_House   | Aqu  | 9.51     |
| Ninth_House    | Pis  | 4.02     |
| Tenth_House    | Ari  | 3.98     |
| Eleventh_House | Tau  | 9.39     |
| Twelfth_House  | Gem  | 15.68    |
+----------------+------+----------+

To export to a file:

```bash
python3 your_script_name.py > file.txt

Example: Retrieving Aspects

from kerykeion import SynastryAspects, AstrologicalSubject

first = AstrologicalSubject("Jack", 1990, 6, 15, 15, 15, "Roma", "IT")
second = AstrologicalSubject("Jane", 1991, 10, 25, 21, 0, "Roma", "IT")

name = SynastryAspects(first, second)
aspect_list = name.get_relevant_aspects()
print(aspect_list[0])
#> {'p1_name': 'Sun', 'p1_abs_pos': 84.17867971515636, 'p2_name': 'Sun', 'p2_abs_pos': 211.90472999502984, 'aspect': 'trine', 'orbit': 7.726050279873476, 'aspect_degrees': 120, 'color': '#36d100', 'aid': 6, 'diff': 127.72605027987348, 'p1': 0, 'p2': 0}

Ayanamsa (Sidereal Modes)

By default, the zodiac type is Tropical. To use Sidereal, specify the sidereal mode:

johnny = AstrologicalSubject(
    "Johnny Depp", 1963, 6, 9, 0, 0,
    "Owensboro", "US",
    zodiac_type="Sidereal",
    sidereal_mode="LAHIRI"
)

More examples here.

Full list of supported sidereal modes here.

House Systems

By default, houses are calculated using Placidus. Configure a different house system as follows:

johnny = AstrologicalSubject(
    "Johnny Depp", 1963, 6, 9, 0, 0,
    "Owensboro", "US",
    houses_system="M"
)

More examples here.

Full list of supported house systems here.

So far all the available houses system in the Swiss Ephemeris are supported but the Gauquelin Sectors.

Perspective Type

By default, Kerykeion uses the Apparent Geocentric perspective (the most standard in astrology). Other perspectives (e.g., Heliocentric) can be set this way:

johnny = AstrologicalSubject(
    "Johnny Depp", 1963, 6, 9, 0, 0,
    "Owensboro", "US",
    perspective_type="Heliocentric"
)

More examples here.

Full list of supported perspective types here.

Themes

Kerykeion provides several chart themes:

• Classic (default)
• Dark
• Dark High Contrast
• Light

Each theme offers a distinct visual style, allowing you to choose the one that best suits your preferences or presentation needs. If you prefer more control over the appearance, you can opt not to set any theme, making it easier to customize the chart by overriding the default CSS variables. For more detailed instructions on how to apply themes, check the documentation

Here's an example of how to set the theme:

from kerykeion import AstrologicalSubject, KerykeionChartSVG

dark_theme_subject = AstrologicalSubject("John Lennon - Dark Theme", 1940, 10, 9, 18, 30, "Liverpool", "GB")
dark_theme_natal_chart = KerykeionChartSVG(dark_high_contrast_theme_subject, theme="dark_high_contrast")
dark_theme_natal_chart.makeSVG()

Alternative Initialization

Create an AstrologicalSubject from a UTC ISO 8601 string:

subject = AstrologicalSubject.get_from_iso_utc_time(
    "Johnny Depp", "1963-06-09T05:00:00Z", "Owensboro", "US"
)

If you set online=True, provide a geonames_username to allow city-based geolocation:

from kerykeion.astrological_subject import AstrologicalSubject

subject = AstrologicalSubject.get_from_iso_utc_time(
    "Johnny Depp", "1963-06-09T05:00:00Z", "Owensboro", "US", online=True
)

Lunar Nodes (Rahu & Ketu)

Kerykeion supports both True and Mean Lunar Nodes:

• True North Lunar Node: "true_node" (name kept without "north" for backward compatibility).
• True South Lunar Node: "true_south_node".
• Mean North Lunar Node: "mean_node" (name kept without "north" for backward compatibility).
• Mean South Lunar Node: "mean_south_node".

In instances of the AstrologicalSubject class, all of them are active by default.

In instances of the classes used to generate aspects and SVG charts, only the mean nodes are active. To activate the true nodes, you need to pass the active_points parameter to the KerykeionChartSVG class.

Example:

from kerykeion import AstrologicalSubject, KerykeionChartSVG

subject = AstrologicalSubject("John Lennon", 1940, 10, 9, 18, 30, "Liverpool", "GB")

chart = KerykeionChartSVG(
    subject,
    active_points=[
        "Sun", 
        "Moon", 
        "Mercury", 
        "Venus", 
        "Mars", 
        "Jupiter", 
        "Saturn",
        "Uranus", 
        "Neptune", 
        "Pluto", 
        "Mean_Node", 
        "Mean_South_Node", 
        "True_Node",       # Activates True North Node 
        "True_South_Node", # Activates True South Node
        "Ascendant",
        "Medium_Coeli", 
        "Descendant", 
        "Imum_Coeli"
    ]
)
chart.makeSVG()

JSON Support

You can serialize the astrological subject (the base data used throughout the library) to JSON:

from kerykeion import AstrologicalSubject

johnny = AstrologicalSubject("Johnny Depp", 1963, 6, 9, 0, 0, "Owensboro", "US")

print(johnny.json(dump=False, indent=2))

Auto Generated Documentation

You can find auto-generated documentation here. Most classes and functions include docstrings.

Development

Clone the repository or download the ZIP via the GitHub interface.

Integrating Kerykeion into Your Project

If you would like to incorporate Kerykeion’s astrological features into your application, please reach out via email. Whether you need custom features, support, or specialized consulting, I am happy to discuss potential collaborations.

License

This project is covered under the AGPL-3.0 License. For detailed information, please see the LICENSE file. If you have questions, feel free to contact me at [e-mail].

As a rule of thumb, if you use this library in a project, you should open-source that project under a compatible license. Alternatively, if you wish to keep your source closed, consider using the AstrologerAPI, which is AGPL-3.0 compliant and also helps support the project.

Since the AstrologerAPI is an external third-party service, using it does not require your code to be open-source.

Contributing

Contributions are welcome! Feel free to submit pull requests or report issues.

Citations

If using Kerykeion in published or academic work, please cite as follows:

Battaglia, G. (2025). Kerykeion: A Python Library for Astrological Calculations and Chart Generation.
https://github.com/g-battaglia/kerykeion