Western Secondary Progressions
asterwise_get_western_secondary_progressions
Secondary progressed chart using the day-for-a-year method. Each day after birth symbolises one year of life (1 ephemeris day = 1 tropical year = 365.2421904 days). Returns all 10 progressed planet positions, progressed Ascendant and MC, and the solar arc.
Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
birth | object | yes | Birth data for Western astrology tools (tropical zodiac). Fields: date, time, lat, lon, person_name, timezone, house_system |
response_format | enum: markdown, json | no | Output format: 'markdown' (default) for a readable report, or 'json' for the raw structured payload. |
target_date | string/null | no | Date in YYYY-MM-DD format. Defaults to today when omitted. |
What it covers
Secondary directions: Moon advances ~12°/year of life, Mercury/Venus track close to Sun speed, outer planets crawl. Includes progressed lunation phases internally.
Workflow
BEFORE: asterwise_get_western_natal.
AFTER: asterwise_get_western_solar_arc — compare uniform arc vs individual motion.
Input
birth — WesternBirthData.
target_date (optional YYYY-MM-DD) — the date to progress to. Defaults to today.
Output contract
data.target_date, data.progressed_jd, data.age_years
data.solar_arc (float — ~1° per year)
data.natal_sun_longitude, data.progressed_sun_longitude
data.progressed_planets[] — 10 objects: name, longitude, sign, degree_in_sign, is_retrograde, dignity, dignity_score
data.progressed_ascendant, data.progressed_ascendant_sign
data.progressed_mc, data.progressed_mc_sign
Response format
response_format=json serialises the complete response as indented JSON.
response_format=markdown renders the same data as a human-readable report.
Both modes return identical underlying data.
Compute class
MEDIUM_COMPUTE (~400ms)
Errors
INVALID_PARAMS (local): WesternBirthData validation failures.
INTERNAL_ERROR: Any upstream API failure or timeout → MCP INTERNAL_ERROR
Edge cases:
Progressed ASC uses the actual house calculation at progressed JD (not solar arc approximation) for higher accuracy. Progressed MC uses natal MC + solar arc.
Do not confuse with
asterwise_get_western_solar_arc — all planets move by one uniform arc.
asterwise_get_western_transits_daily — real-time sky, not symbolic progression.
Connect
Remote MCP endpoint: https://mcp.asterwise.com/mcp. Authenticate with Authorization: Bearer <API key> or OAuth. See the MCP setup guide.