GET/v1/western/moon/phase

Western Moon Phase

Calculate the lunar phase for any date using the tropical zodiac, computed at 18:00 UTC on that date. Returns the phase name in Dane Rudhyar's eight 45-degree phases (New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Waning Crescent; each begins at its angle), phase angle, illumination percentage, moon age since the previous exact New Moon, the exact instant of the next principal phase, and principal_phase when a New Moon, First Quarter, Full Moon or Last Quarter falls on the UTC date. Defaults to today (UTC) if no date given.

Request parameters

dateoptional

string | null

Date in YYYY-MM-DD format, years 1-3000. Defaults to today (UTC).

Response fields

success

boolean

True if the request succeeded

message

string

Human-readable status message

data

object

data.date

string

Date in YYYY-MM-DD format

data.phase_name

string

Phase at 18:00 UTC on the date, in Dane Rudhyar's eight 45-degree phases: each phase begins at its angle (New Moon 0-45, Waxing Crescent 45-90, First Quarter 90-135, Waxing Gibbous 135-180, Full Moon 180-225, Waning Gibbous 225-270, Last Quarter 270-315, Waning Crescent 315-360), so the day before a full moon reads Waxing Gibbous. Use principal_phase for the day of an exact phase.

data.phase_angle

number

Sun-Moon elongation in degrees (0-360) at 18:00 UTC. 0=New Moon, 180=Full Moon

data.illumination_pct

number

Percentage of Moon disk illuminated (0-100)

data.moon_age_days

number

Days from the previous exact New Moon to 18:00 UTC on the date (0 to about 29.8)

data.moon_longitude

number

Tropical ecliptic longitude of Moon (0-360)

data.sun_longitude

number

Tropical ecliptic longitude of Sun (0-360)

data.is_waxing

boolean

True if Moon is waxing (phase_angle < 180)

data.next_phase_name

string

Name of the next principal phase (New Moon, First Quarter, Full Moon, Last Quarter) after 18:00 UTC on the date

data.next_phase_date

string | null

UTC date (YYYY-MM-DD) of the exact instant of the next principal phase

data.next_phase_at

string | null

Exact instant of the next principal phase, ISO 8601 UTC (e.g. 2026-10-26T04:11:49Z)

data.computed_at

string | null

Instant the phase, angle, illumination and longitudes are computed for: 18:00 UTC on the date

data.principal_phase

string | null

The principal phase (New Moon, First Quarter, Full Moon or Last Quarter) whose exact instant falls on this UTC date, or null. Marks the one day of each phase, as in published phase tables.

data.principal_phase_at

string | null

Exact instant of principal_phase, ISO 8601 UTC

Errors

api_key_invalid

Invalid API key format.

api_key_missing

API key is missing. Include it in the Authorization header as 'Bearer YOUR_KEY'.

api_key_not_found

The provided API key was not found. Verify the key in your Asterwise dashboard.

api_key_revoked

This API key has been revoked.

burst_limit_exceeded

Too many requests per minute. Please slow down.

internal_error

Something went wrong on our end. Please try again, or contact [email protected] if the problem persists. Include your request_id when contacting support.

ip_rate_limit_exceeded

Too many requests from this IP address. Please slow down.

monthly_usage_limit_exceeded

Monthly API call limit reached. Upgrade your plan to continue.

payload_too_large

Request body exceeds maximum allowed size of 64KB.

subscription_expired

Your subscription has expired. Please renew at asterwise.com/dashboard to continue.

validation_error

The request couldn't be processed. See the 'details' field for specific field-level issues.

Related endpoints

• Biorhythm Cycles
• Eclipses
• Western Moon Phase Calendar
• Planetary hours
• Void-of-course Moon
• Western day view

Request

GET·application/json

curl

curl -X GET "https://api.asterwise.com/v1/western/moon/phase?date=2026-01-01" \
  -H "Authorization: Bearer YOUR_API_KEY"

Python

import asterwise
from asterwise.api.western_astrology_api import WesternAstrologyApi

configuration = asterwise.Configuration(
    host="https://api.asterwise.com",
    access_token="YOUR_API_KEY",
)

with asterwise.ApiClient(configuration) as client:
    api = WesternAstrologyApi(client)
    result = api.western_moon_phase(date="2026-01-01")
    print(result)

TypeScript

import { createClient, createConfig, westernMoonPhase } from 'asterwise';

const client = createClient(createConfig({
  baseUrl: 'https://api.asterwise.com',
  headers: { Authorization: 'Bearer YOUR_API_KEY' },
}));

const result = await westernMoonPhase({
  client,
  query: {
      "date": "2026-01-01"
  },
});

console.log(result.data);

Response

200 OK·application/jsonsigned

{
  "success": true,
  "message": "success",
  "data": {
    "date": "2026-01-01",
    "phase_name": "Waxing Gibbous",
    "phase_angle": 156.6555,
    "illumination_pct": 95.91,
    "moon_age_days": 12.68,
    "moon_longitude": 77.98827,
    "sun_longitude": 281.332736,
    "is_waxing": true,
    "next_phase_name": "Full Moon",
    "next_phase_date": "2026-01-03",
    "next_phase_at": "2026-01-03T10:02:55Z",
    "computed_at": "2026-01-01T18:00:00Z",
    "principal_phase": null,
    "principal_phase_at": null
  }
}