Planetary Hours

Compute all 24 planetary hours for a given date and location, following the traditional Chaldean order. Each hour is ruled by one of the 7 visible planets.

GET  /v1/planetary-hours
POST /v1/planetary-hours

Credit cost: 1

Parameters

No bodies or house system parameters are needed — planetary hours depend only on sunrise/sunset times.

Response

{
  "data": {
    "day_of_week": 3,
    "day_ruler": "mercury",
    "sunrise_jd": 2460400.75,
    "sunset_jd": 2460401.0,
    "next_sunrise_jd": 2460401.75,
    "hours": [
      {
        "hour_number": 1,
        "is_diurnal": true,
        "period_hour": 1,
        "ruler": "mercury",
        "jd_start": 2460400.75,
        "jd_end": 2460400.771
      }
    ],
    "current_hour_index": 5
  },
  "meta": {
    "credits_used": 1,
    "..."
  }
}

Fields:

• day_of_week — Day of week (0 = Monday, 6 = Sunday)
• day_ruler — The planet ruling the day (e.g., Wednesday = Mercury)
• sunrise_jd / sunset_jd / next_sunrise_jd — Julian Day values for sunrise, sunset, and the following sunrise
• hours — Array of 24 planetary hours, each with:
  • hour_number — Sequential number (1-24)
  • is_diurnal — true for daytime hours (1-12), false for nighttime (13-24)
  • period_hour — Hour within the period (1-12 for day, 1-12 for night)
  • ruler — Ruling planet for this hour
  • jd_start / jd_end — Start and end times as Julian Day values
• current_hour_index — 0-based index into the hours array for the hour containing the requested datetime (if the datetime falls within the day's hours)

Chaldean order

The planetary hours cycle through the 7 visible planets in descending orbital period: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon — then repeat. The first hour of each day is ruled by the day's planetary ruler.

Examples

Planetary hours for today

curl "https://api.morphemeris.com/v1/planetary-hours?\
datetime=2024-03-20T12:00:00Z\
&lat=40.7128&lon=-74.006" \
  -H "Authorization: Bearer morphemeris_live_YOUR_KEY"

const res = await fetch(
  "https://api.morphemeris.com/v1/planetary-hours?" + new URLSearchParams({
    datetime: "2024-03-20T12:00:00Z",
    lat: "40.7128", lon: "-74.006",
  }),
  { headers: { Authorization: "Bearer morphemeris_live_YOUR_KEY" } }
);
const { data } = await res.json();
console.log(`Current hour ruled by: ${data.hours[data.current_hour_index].ruler}`);

import requests

res = requests.get(
    "https://api.morphemeris.com/v1/planetary-hours",
    params={
        "datetime": "2024-03-20T12:00:00Z",
        "lat": 40.7128, "lon": -74.006,
    },
    headers={"Authorization": "Bearer morphemeris_live_YOUR_KEY"},
)
data = res.json()["data"]
current = data["hours"][data["current_hour_index"]]
print(f"Current hour ruled by: {current['ruler']}")

Tips

• Daytime hours are not 60 minutes long — they divide the time between sunrise and sunset into 12 equal parts. Near the equinoxes, each planetary hour is close to 60 minutes; near the solstices, daytime hours can be significantly longer or shorter.
• Nighttime hours similarly divide sunset-to-next-sunrise into 12 equal parts.
• Planetary hours are used in electional astrology to choose auspicious times for activities. For example, a Venus hour might be chosen for matters of love or art, while a Jupiter hour might be preferred for business or legal matters.
• The current_hour_index field lets you quickly determine which planetary hour is active at the requested time without comparing Julian Day values yourself.
• At extreme latitudes (near the Arctic or Antarctic circles), sunrise and sunset times may be unusual or absent during polar day/night. The endpoint uses standard atmospheric refraction for sunrise/sunset calculation.