The Python Alternative to the Swiss Ephemeris

import os
from datetime import datetime
from fastapi import FastAPI, HTTPException
from moira.facade import Moira, HouseSystem

app = FastAPI(title="Astrology Service")

# Planetary calculations require a JPL kernel supplied by the operator.
moira = Moira(kernel_path=os.environ["MOIRA_KERNEL_PATH"])

@app.get("/api/chart")
def get_chart(birth_iso: str, lat: float, lon: float):
    dt = datetime.fromisoformat(birth_iso.replace("Z", "+00:00"))
    if dt.tzinfo is None:
        raise HTTPException(422, "birth_iso must include a UTC offset")
    
    # 1. Planetary positions under the selected kernel and policies
    chart = moira.chart(dt)
    
    # 2. House cusps for the supplied observer coordinates
    houses = moira.houses(dt, latitude=lat, longitude=lon, system=HouseSystem.PLACIDUS)
    
    # 3. Inter-planetary aspects with customizable orb policies
    aspects = moira.aspects(chart)
    
    return {
        "ascendant": houses.asc,
        "midheaven": houses.mc,
        "planets": {
            name: {"lon": p.longitude, "speed": p.speed}
            for name, p in chart.planets.items()
        },
        "houses": houses.cusps,
        "aspects": [
            {"b1": a.body1, "b2": a.body2, "type": str(a.aspect), "orb": round(a.orb, 2)}
            for a in aspects
        ],
    }

This example requires an installed package and a compatible JPL kernel at MOIRA_KERNEL_PATH. It rejects timezone-naive input rather than guessing a civil-time offset.