When To Use It

Use tertiary when you want a quicker symbolic progression system that emphasizes shorter emotional and situational cycles.

How It Differs From Secondary

The request contract is the same shape as secondary, but the symbolic timing rule is faster. In practice, tertiary charts and event searches produce denser change over shorter windows.

Minimal Request

curl -X POST "https://api.freeastroapi.com/api/v1/western/progressions/tertiary" \
 -H "Content-Type: application/json" \
 -H "x-api-key: YOUR_API_KEY" \
 -d '{
  "natal": {
    "name": "User",
    "datetime": "1990-01-01 12:00",
    "time_known": true,
    "location": {
      "city": "London",
      "lat": 51.5074,
      "lng": -0.1278,
      "tz_str": "AUTO"
    }
  },
  "tertiary_progression": {
    "target_date": "2026-03-30"
  }
}'

Table Mode

curl -X POST "https://api.freeastroapi.com/api/v1/western/progressions/tertiary?response_mode=table" \
 -H "Content-Type: application/json" \
 -H "x-api-key: YOUR_API_KEY" \
 -d '{
  "natal": {
    "name": "User",
    "datetime": "1990-01-01 12:00",
    "time_known": true,
    "location": {
      "city": "London",
      "lat": 51.5074,
      "lng": -0.1278,
      "tz_str": "AUTO"
    }
  },
  "tertiary_progression": {
    "target_date": "2026-03-30"
  }
}'

Real API Response Example

Captured from the live API on April 14, 2026 using the minimal request above.

{
  "meta": {
    "endpoint": "progressions_chart",
    "version": "v1",
    "system": "tertiary",
    "zodiac_type": "tropical",
    "house_system": "placidus",
    "calculation_method": "tertiary_progressions_day_for_lunar_month",
    "target_date": "2026-03-30",
    "target_datetime": "2026-03-30T00:00:00Z",
    "orb_deg": 1,
    "generated_at": "2026-04-14T15:54:52Z"
  },
  "progression_basis": {
    "age_years_decimal": 36.240337,
    "progressed_days_after_birth": 448.230141,
    "natal_datetime_utc": "1990-01-01T12:00:00Z",
    "progressed_datetime_utc": "1991-03-25T17:31:24Z"
  },
  "progressed_chart": {
    "points": {
      "sun": {
        "name": "Sun",
        "longitude_deg": 4.567463,
        "longitude_text": "04°34' Ari",
        "latitude_deg": -0.00003,
        "distance_au": 0.997311,
        "sign": {
          "name": "Aries",
          "index": 0,
          "abbr": "Ari"
        },
        "position_in_sign_deg": 4.567463,
        "house": 7,
        "retrograde": false
      },
      "moon": {
        "name": "Moon",
        "longitude_deg": 126.855787,
        "longitude_text": "06°51' Leo",
        "latitude_deg": -0.989085,
        "distance_au": 0.002493,
        "sign": {
          "name": "Leo",
          "index": 4,
          "abbr": "Leo"
        },
        "position_in_sign_deg": 6.855787,
        "house": 11,
        "retrograde": false
      },
      "mercury": {
        "name": "Mercury",
        "longitude_deg": 23.040506,
        "longitude_text": "23°02' Ari",
        "latitude_deg": 2.136624,
        "distance_au": 0.944855,
        "sign": {
          "name": "Aries",
          "index": 0,
          "abbr": "Ari"
        },
        "position_in_sign_deg": 23.040506,
        "house": 8,
        "retrograde": false
      }
    },
    "angles": {
      "ascendant": {
        "longitude_deg": 176.756,
        "longitude_text": "26°45' Vir",
        "sign": {
          "name": "Virgo",
          "index": 5,
          "abbr": "Vir"
        },
        "position_in_sign_deg": 26.756
      },
      "midheaven": {
        "longitude_deg": 85.778,
        "longitude_text": "25°47' Gem",
        "sign": {
          "name": "Gemini",
          "index": 2,
          "abbr": "Gem"
        },
        "position_in_sign_deg": 25.778
      }
    }
  },
  "aspects": {
    "progressed_to_natal": [
      {
        "id": "p_sun_square_n_jupiter",
        "aspect": {
          "name": "square",
          "angle_deg": 90
        },
        "progressed_point": "sun",
        "natal_point": "jupiter",
        "orb_deg": 0.581,
        "separation_deg": 90.581,
        "applying": true,
        "exact": false,
        "exact_date": "2026-04-16T08:00:56Z",
        "polarity": "hard",
        "strength": 0.494,
        "category": "major",
        "interpretation_key": "progressed_sun_square_natal_jupiter"
      },
      {
        "id": "p_neptune_conjunction_n_saturn",
        "aspect": {
          "name": "conjunction",
          "angle_deg": 0
        },
        "progressed_point": "neptune",
        "natal_point": "saturn",
        "orb_deg": 0.946,
        "separation_deg": 0.946,
        "applying": false,
        "exact": false,
        "polarity": "neutral",
        "strength": 0.054,
        "category": "major",
        "interpretation_key": "progressed_neptune_conjunction_natal_saturn"
      },
      {
        "id": "p_neptune_sextile_n_pluto",
        "aspect": {
          "name": "sextile",
          "angle_deg": 60
        },
        "progressed_point": "neptune",
        "natal_point": "pluto",
        "orb_deg": 0.49,
        "separation_deg": 59.51,
        "applying": false,
        "exact": false,
        "polarity": "soft",
        "strength": 0.51,
        "category": "major",
        "interpretation_key": "progressed_neptune_sextile_natal_pluto"
      }
    ],
    "progressed_to_progressed": [
      {
        "id": "p_saturn_sextile_p_sun",
        "aspect": {
          "name": "sextile",
          "angle_deg": 60
        },
        "point_1": "saturn",
        "point_2": "sun",
        "orb_deg": 0.125,
        "separation_deg": 59.875,
        "applying": true,
        "exact": false,
        "exact_date": "2026-04-03T00:40:46Z",
        "polarity": "soft",
        "strength": 0.999,
        "category": "major",
        "interpretation_key": "progressed_saturn_sextile_progressed_sun"
      },
      {
        "id": "p_jupiter_trine_p_sun",
        "aspect": {
          "name": "trine",
          "angle_deg": 120
        },
        "point_1": "jupiter",
        "point_2": "sun",
        "orb_deg": 0.981,
        "separation_deg": 119.019,
        "applying": false,
        "exact": false,
        "exact_date": "2026-03-01T05:52:58Z",
        "polarity": "soft",
        "strength": 0.022,
        "category": "major",
        "interpretation_key": "progressed_jupiter_trine_progressed_sun"
      },
      {
        "id": "p_ic_opposition_p_mars",
        "aspect": {
          "name": "opposition",
          "angle_deg": 180
        },
        "point_1": "ic",
        "point_2": "mars",
        "orb_deg": 0.111,
        "separation_deg": 179.889,
        "applying": true,
        "exact": false,
        "exact_date": "2026-03-30T00:00:00Z",
        "polarity": "hard",
        "strength": 0.889,
        "category": "major",
        "interpretation_key": "progressed_ic_opposition_progressed_mars"
      }
    ]
  }
}

Related Utility Pages

Exact ingresses, exact aspects, and calendar are also available for tertiary through the shared utility docs pages.