GET /v1/void-of-course — Determine if the Moon is void of course and find its last aspect.

Void-of-Course Moon

Analyze whether the Moon is void of course — meaning it will make no more major aspects before leaving its current sign.

Text

GET  /v1/void-of-course
POST /v1/void-of-course

Credit cost: 1

Parameters

Parameter	Type	Required	Default	Description
`datetime`	string	One of `datetime` or `jd`	—	ISO 8601 UTC datetime
`jd`	number	One of `datetime` or `jd`	—	Julian Day in UT1
`bodies`	string	No	`"planets"`	Bodies to check aspects against
`aspects`	string	No	Major 7	Comma-separated aspect types to consider
`orb`	number	No	—	Global orb override in degrees

No location is required — void-of-course analysis uses ecliptic longitudes and speeds.

Response

JSON

{
  "data": {
    "is_void": true,
    "moon_longitude": 245.67,
    "degrees_until_sign_change": 4.33,
    "next_sign_boundary": 250.0,
    "last_aspect": {
      "body_a": "moon",
      "body_b": "saturn",
      "aspect": "trine",
      "angle": 120.0,
      "orb": 0.45,
      "applying": false
    }
  },
  "meta": {
    "credits_used": 1,
    "..."
  }
}

Fields:

is_void — Whether the Moon is void of course
moon_longitude — Moon's current ecliptic longitude
degrees_until_sign_change — Degrees remaining before the Moon enters the next sign
next_sign_boundary — The ecliptic longitude of the next sign boundary
last_aspect — The most recent aspect the Moon completed (or null if no aspects were found in the current sign). Includes the aspect type, angle, orb, and applying/separating status.

Examples

Is the Moon void of course right now?

Bash

curl "https://api.morphemeris.com/v1/void-of-course?\
datetime=2024-03-20T12:00:00Z" \
  -H "Authorization: Bearer morphemeris_live_YOUR_KEY"

javascript

const res = await fetch(
  "https://api.morphemeris.com/v1/void-of-course?" + new URLSearchParams({
    datetime: "2024-03-20T12:00:00Z",
  }),
  { headers: { Authorization: "Bearer morphemeris_live_YOUR_KEY" } }
);
const { data } = await res.json();
console.log(data.is_void ? "Moon is void of course" : "Moon is not void");

Python

import requests

res = requests.get(
    "https://api.morphemeris.com/v1/void-of-course",
    params={"datetime": "2024-03-20T12:00:00Z"},
    headers={"Authorization": "Bearer morphemeris_live_YOUR_KEY"},
)
data = res.json()["data"]
print("Void" if data["is_void"] else "Not void")

With custom aspects

Bash

curl "https://api.morphemeris.com/v1/void-of-course?\
datetime=2024-03-20T12:00:00Z\
&aspects=conjunction,opposition,trine,square,sextile" \
  -H "Authorization: Bearer morphemeris_live_YOUR_KEY"

javascript

const res = await fetch(
  "https://api.morphemeris.com/v1/void-of-course?" + new URLSearchParams({
    datetime: "2024-03-20T12:00:00Z",
    aspects: "conjunction,opposition,trine,square,sextile",
  }),
  { headers: { Authorization: "Bearer morphemeris_live_YOUR_KEY" } }
);
const { data } = await res.json();

Python

import requests

res = requests.get(
    "https://api.morphemeris.com/v1/void-of-course",
    params={
        "datetime": "2024-03-20T12:00:00Z",
        "aspects": "conjunction,opposition,trine,square,sextile",
    },
    headers={"Authorization": "Bearer morphemeris_live_YOUR_KEY"},
)
data = res.json()

Tips

Void-of-course Moon is a key concept in horary and electional astrology. Traditionally, actions begun during a void Moon are said to "come to nothing" — they may not produce the intended results.
The default aspect set (conjunction, opposition, trine, square, sextile, semi-sextile, quincunx) is the traditional set used for void-of-course determination. Some practitioners use only the Ptolemaic 5 (excluding semi-sextile and quincunx) — use the aspects parameter to customize.
The Moon changes signs roughly every 2.5 days. Void-of-course periods can last anywhere from a few minutes to over a day.
The bodies parameter controls which planets are checked for aspects. The default ("planets") includes Sun through Pluto. Some traditional practitioners only consider the 7 visible planets (Sun through Saturn).
The Moon must be included in the requested bodies for this endpoint to work. If the Moon is not in the computed positions, the endpoint returns a 400 error with a suggestion to include it.

Void-of-Course Moon

Void-of-Course Moon

Parameters

Response

Examples

Is the Moon void of course right now?

With custom aspects

Tips

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