Western Astrology

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.

get/v1/western/moon/phase

Request

  • Base URL: https://api.asterwise.com
  • URL: https://api.asterwise.com/v1/western/moon/phase
  • Auth: HTTP bearer

Query parameters

datestring nullable

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

Example:2026-05-01

Response

Successful Response

successboolean

True if the request succeeded

messagestring

Human-readable status message

Example response

{
  "data": {
    "phase_name": "Full Moon",
    "illumination_pct": 99.79,
    "next_phase_at": "2026-10-26T04:11:49Z",
    "computed_at": "2026-05-01T18:00:00Z",
    "principal_phase": "Full Moon"
  }
}

Changes

No recorded changes to this operation across all 2 revisions of this API.