What's the difference between primary directions and arc directions?

Primary directions rotate the promissor through the diurnal arc to meet the significator in three dimensions. Earth's rotation is the engine, and the math involves oblique ascension, polar elevation, and semi-arcs. Arc directions advance every body in the chart by the same fixed rate per year (Naibod, lunar arc, or chart-ruler arc) and then run aspect detection against natal positions. Primary directions are slower to compute and physically grounded; arc directions are faster and symbolic. The API ships both.

Which key does the API use: Ptolemy, Naibod, or both?

Default is Naibod (0.9856473° per year), Gansten's preferred key and the Renaissance standard. You can pass key=ptolemy for the original 1° per year rate Lilly used, key=true_solar for the natal Sun's actual right ascension travel, key=lunar for the scaled Moon rate, or key=chart_ruler for the personalized Ascendant-lord rate. The response includes arc_degrees and age_years for every hit, so you can compare keys side by side on the same chart.

How accurate are the calculations?

Arc tolerance is ±0.001° versus Morinus (the open-source Placidus semi-arc reference) and Solar Fire v9. Date tolerance on the resulting calendar date is ±2 days. The API uses Swiss Ephemeris with the SEFLG_SWIEPH and SEFLG_EQUATORIAL flags for right ascension and declination, which is the same engine professional astrology software relies on. Three published validation cases (Princess Diana, JFK, Hitler) are tested on every commit and must match their published arcs to three decimals.

Does the API support mundo and zodiacal directions?

Yes, both. Pass level=mundo to direct the promissor's actual body with its real declination to the significator's mundane position (Gansten's rigorous 3D method). Pass level=zodiaco to direct the promissor's ecliptic longitude point with zero latitude (the method Solar Fire and Janus default to). Pass level=both to get separate hit lists for each: no double-counting, no merged values. Mundo and zodiacal often produce different exact dates for the same promissor-significator pair, which is the point.

How does this compare to Solar Fire, Janus, and Morinus?

Solar Fire v9 ($199 desktop license) is the industry standard for primary directions, and our API matches its arcs to ±0.01°. Janus ($89 desktop) implements a similar Placidus semi-arc method, and we match it to the same tolerance. Morinus is the open-source reference implementation we cross-check against on every commit. The trade-off: those tools are desktop apps with GUIs and chart drawing. We're a REST API with sub-300ms response, MCP tool registration, and a free tier. Pick the API when you're building software; pick Solar Fire when you're consulting clients directly.

How much does it cost?

$11 per month for 1,000 requests on the Starter plan. $37 per month for 55,000 requests on the Professional plan. $99 per month for 220,000 requests and all endpoints on the Business plan. Free tier: 50 requests per month forever, no credit card required. Every plan includes primary directions and all three arc-direction endpoints (Naibod, lunar arc, chart-ruler arc).

How do I direct the Moon vs an angle?

Pass the Moon as the significator (significators=["Moon"]) when you want to time Moon-related topics: emotional events, household, the body. Pass an angle (Ascendant, Medium Coeli, Pars Fortunae) when you want to time life-direction events tied to that angle. The classical significator set is Ascendant, MC, Sun, Moon, and Lot of Fortune. The endpoint accepts any combination. Different significators have different poles and produce different arcs for the same promissor; that's the technique's strength.

What is converse motion?

Converse motion reverses the role: instead of the promissor moving forward to meet the significator, the significator moves forward to meet the promissor. The arc is calculated as OA_significator - OA_promissor*. The crucial rule, which Gansten emphasizes in chapter 5, is that the significator's pole still governs the calculation even when the motion is reversed. The include_converse param controls whether converse hits appear in the response (default true). Converse directions are debated in the literature: some authors treat them as predictive, others as symbolic.

How does the API handle high-latitude births and circumpolar bodies?

For births above |φ| > 66°, tan(φ) · tan(δ) can exceed 1, which means the body is circumpolar and its semi-arc is undefined. The API flags those bodies in metadata.polar_flags and skips them rather than fabricate a clamped value (clamping would falsify the chart). For circumpolar promissors that never rise or set, only mundane directions to the MC or IC are meaningful, so those are the only hits returned for that body. Polar handling is one of the bugs that breaks naive primary-direction code, and the API has explicit tests for it.

Can I get directions for fixed stars like Regulus or Algol?

Yes. Pass include_fixed_stars=true and the API will compute mundo directions to Regulus, Spica, Algol, and Antares as promissors. Fixed stars are most useful in mundo, because their declination layer matters. They're commonly added in traditional practice for high-stakes timing: Regulus for honors and downfall, Algol for danger and reversal. Fixed-star directions are returned with notes="fixed_star" so you can filter or display them separately in your UI.

What aspects are supported?

The Ptolemaic set: conjunction, sextile, square, trine, and opposition. These are the classical aspects used in primary directions from Ptolemy through Lilly and Morin. Modern minor aspects (semi-square, sesquiquadrate, quintile) are not included by default because classical primary directions stop at the Ptolemaic set. The aspects param accepts any subset of the five if you want to filter (e.g., aspects=["conjunction","opposition"] for just the hard angles).

Is the endpoint sect-aware?

Yes. Sect (day chart vs night chart) is detected from the Sun's house position and respected in significator selection: diurnal Lot of Fortune uses ASC + Moon - Sun, nocturnal uses ASC + Sun - Moon. Sect-awareness is also surfaced in metadata so you can filter hits by day-sect or night-sect bodies. This matters because some traditional schools weight directions to sect-light planets (Sun by day, Moon by night) more heavily than the other.

What's the response format?

JSON. The data.hits array contains PrimaryDirectionHit objects with promissor, significator, aspect, direction_type (direct/converse), level (mundo/zodiaco), arc_degrees, key, age_years, exact_date, pole_of_significator, and an optional notes field for flags like antiscion, fixed_star, or polar_flagged. Hits are sorted ascending by age_years. Metadata includes calculation_method, key_used, and polar_flags listing every body that was skipped. Standardized celestial names match the rest of the v3 API.

Can I run primary directions from an AI agent like Claude or GPT?

Yes. The endpoint is registered as an MCP tool, so Claude Code, GPT, and any MCP-aware agent can call it directly without writing custom HTTP plumbing. The tool accepts the same parameters as the REST endpoint (key, level, include_converse, significators, promissors, aspects, max_age). Pair it with the natal-chart MCP tool to compute a chart and direct it in a single agent turn.

What programming languages can I call the API from?

Any language with an HTTP client. The API speaks JSON over HTTPS. Code examples in the docs cover Python (requests, httpx), JavaScript/TypeScript (fetch, axios), Ruby, Go, PHP, and curl. There are also typed SDK wrappers for Python and TypeScript that handle authentication, retries, and response parsing. MCP tool registration covers Claude Code, OpenAI Agents, and LangChain.

How does primary directions fit alongside profections, Firdaria, and Zodiacal Releasing?

Primary directions give you exact dates for major life events; profections, Firdaria, and Zodiacal Releasing give you the topical frame and time-lord ruler for each period. The /timing/timeline endpoint returns all four techniques aligned on the same date so you can build full traditional forecast reports in one call. Run primary directions for the dates, then layer profection LOY, Firdaria L1/L2, and ZR L1/L2 on top to read the topic.

Predictive Timing Suite

Primary Directions Done the Gansten Way

Placidus semi-arc 3D method per Gansten's Primary Directions: Astrology's Old Master Technique (2009).

Mundo and zodiacal directions. Naibod, Ptolemy, true solar, lunar arc, and chart-ruler arc keys. Direct and converse motion. Swiss Ephemeris precision. Sub-300ms response.

View Live Demo

3D Semi-Arc

Placidus method per Gansten (2009)

5 Keys

Ptolemy, Naibod, true solar, lunar, chart-ruler

±0.001°

Arc tolerance vs Morinus / Solar Fire

<300ms

P95 response time

Swiss Ephemeris arc-second precision

Validated against Morinus and Solar Fire

99.9% uptime SLA

2D ecliptic shortcuts instead of true Placidus semi-arc 3D directions
No pole of significator computation, so every direction uses geographic latitude (the most common bug per Hand and Gansten)
Zodiacal directions only, no mundo (in mundo) directions with actual declination
Single key (usually Ptolemy 1°/year), no Naibod, no lunar arc, no chart-ruler arc
No converse motion, no sect-awareness, no polar-latitude handling

Upgrade to

Gansten's canonical Placidus semi-arc 3D method: oblique ascension under each significator's own pole
Pole of significator computed per body via tan(pole) = sin(W) · tan(φ), then promissor directed to that pole
Mundo and zodiacal directions both available, with Ptolemaic aspects on the ecliptic
5 keys: Ptolemy (1°/y), Naibod (0.9856473°/y), true solar arc, lunar arc, chart-ruler arc
Direct and converse motion, sect-aware, polar-latitude bodies flagged not silently clamped

Primary Directions API at a Glance

The math that traditional astrologers actually want, exposed as JSON

<300ms

P95 Response Time

Placidus semi-arc 3D

Method

Time Keys

±0.001°

Arc Tolerance

Primary Directions API Feature List

Everything the endpoint exposes

Placidus Semi-Arc 3D Method

Canonical implementation per Gansten (2009), the standard 3D method used by Morinus and Solar Fire

Oblique ascension via semi-arc, pole of significator computed per body

Mundo Directions

Promissor's actual body with real declination rotated to the significator's mundane position

level=mundo, the rigorous 3D method Gansten teaches

Zodiacal Directions

Promissor's ecliptic longitude point directed with zero latitude, Ptolemaic aspects on ecliptic

level=zodiaco, the modern textbook method Solar Fire defaults to

Naibod Key (Default)

0.9856473° per year, the mean tropical Sun motion, Gansten's preferred rate

key=naibod, 360° ÷ 365.2422 days

Ptolemy Key

1° of right ascension per year, the original Ptolemaic rate used by Lilly

key=ptolemy, the simplest historic key

True Solar Arc Key

Actual right ascension travel of natal Sun, varies 0.953°–1.019°/year

key=true_solar, modern precision-school choice

Lunar Arc Key

Progressed Moon's daily motion scaled to ~0.99°/year via ÷13.36

key=lunar, Moon-significator timing

Chart-Ruler Arc Key

Personalized rate from the Ascendant lord's daily motion

key=chart_ruler, Mars ruler runs fast, Saturn ruler runs slow

Direct and Converse Motion

Both directions returned by default; significator's pole governs both

include_converse=true (default), Gansten ch. 5

Configurable Significators

Classical set (ASC, MC, Sun, Moon, Pars Fortunae) plus optional Descendant, IC, year lord

significators param accepts standardized celestial names

Optional Fixed Stars and Antiscia

Add Regulus, Spica, Algol, Antares as promissors; optionally include antiscion points

include_fixed_stars=true, include_antiscia=true

Polar-Latitude Edge Case Handling

Bodies above |φ| > 66° flagged polar_undefined instead of clamped or silently dropped

metadata.polar_flags lists every skipped body

Primary Directions API: Placidus Semi-Arc 3D, Gansten Method

The canonical 3D implementation with mundo, zodiacal, and 5 arc keys

Primary directions rotate a promissor (a natal planet or aspect point) through the diurnal arc until it meets a significator (Ascendant, Midheaven, Sun, Moon, or Lot of Fortune). The Earth's rotation is the engine: roughly 1° of right ascension crossing the meridian per ~4 minutes of clock time equals about 1 year of life under the Ptolemy key. Per Martin Gansten's Primary Directions: Astrology's Old Master Technique (Wessex Astrologer, 2009), the Placidus semi-arc method is the canonical 3D implementation. Most APIs use 2D ecliptic shortcuts that quietly drop the polar elevation step. We don't. Our /api/v3/directions/primary endpoint computes oblique ascension via semi-arc, derives the polar elevation of each significator from its position between meridian and horizon, then directs the promissor under that pole, not under geographic latitude.

What is Gansten's Placidus semi-arc 3D method?

The Placidus semi-arc method directs the promissor through the diurnal arc to the position of the significator in three dimensions, not just along the ecliptic.

The algorithm has five steps.

First, compute oblique ascension and descension via the ascensional difference AD = arcsin(tan(φ) · tan(δ)), where φ is geographic latitude and δ is the body's declination.

Second, get the significator's diurnal semi-arc (90° + AD for northern declination, northern latitude) and nocturnal semi-arc (90° - AD).

Third, compute the polar elevation of the significator using Gansten's formulation: tan(pole) = sin(W) · tan(φ), where W is the proportional mundane distance between meridian and horizon.

Fourth, direct the promissor to that pole (not to geographic latitude).

Fifth, the arc of direction equals OA_promissor* minus OA_significator for direct motion, or the reverse for converse.

Most APIs skip step three and step four, which is the most common bug Robert Hand and Gansten flag.

We don't.

Pole of significator computed per body via tan(pole) = sin(W) · tan(φ)

1 min read

Mundo vs zodiacal: which one should you direct?

There are two valid Placidus methods, and the API supports both.

In mundo means the promissor's actual body, with its real declination, is rotated to the significator's mundane position.

This is the rigorous 3D method Gansten teaches and the one Morinus uses as its reference.

In zodiaco means the promissor's ecliptic longitude point is reduced to the equator with zero latitude before being directed.

Aspects (sextile, square, trine, opposition) are taken on the ecliptic first, then the resulting longitude point is directed.

Most modern software (Solar Fire, Janus) defaults to zodiacal with latitude.

The level param accepts mundo, zodiaco, or both, and the API will return separate hits for each.

Mundo directions reveal aspects that zodiacal misses because the declination layer reshapes the timing.

Zodiacal is what most modern textbooks teach, so it's the bridge for clients moving from Solar Fire.

level=mundo, zodiaco, or both: two separate hit lists, no double-counting

1 min read

Which time key: Ptolemy, Naibod, true solar, lunar, or chart-ruler arc?

An arc of direction is just degrees.

You need a key to convert degrees into years of life.

The API supports five.

Ptolemy: exactly 1° per year, the original key used by Lilly.

Naibod: 0.9856473° per year, the mean tropical Sun's daily motion (360° divided by 365.2422 days), Gansten's preferred key.

True solar arc: the actual right ascension travel of the natal Sun between the birth date and birth date plus N days, the modern precision-school choice.

Lunar arc: progressed Moon's daily motion as a yearly rate, scaled (Moon's daily motion ÷ 13.36 ≈ 0.99°/year) so it tracks Sun-equivalent velocity.

Chart-ruler arc: the daily motion of the Ascendant lord, normalized against its mean motion and multiplied by Naibod, producing a personalized rate (Mars ruler runs fast, Saturn ruler runs slow).

Pass key=naibod (default), key=ptolemy, key=true_solar, key=lunar, or key=chart_ruler.

The response includes arc_degrees and age_years for every hit, so you can compare keys side by side.

Default Naibod; Ptolemy, true solar, lunar, and chart-ruler arc all selectable

1 min read

Direct and converse motion, polar handling, life-span cap

Direct motion is the promissor moving forward in right ascension to meet the significator.

Converse is the promissor moving backward; the significator's pole still governs, which is the rule Gansten emphasizes in chapter 5.

The include_converse flag controls whether converse hits are returned alongside direct hits (default true).

For polar handling, the API does not clamp latitude.

Births above |φ| > 66° where tan(φ) · tan(δ) exceeds 1 produce circumpolar bodies with undefined semi-arcs.

We flag those bodies as polar_undefined in metadata.polar_flags and skip them rather than fabricate a value.

Circumpolar promissors never rise or set, so only mundane directions to MC or IC are meaningful, and the API returns those alone.

For life-span normalization, the API applies a max_age cap (default 90 years, configurable up to 100).

Arcs over 100° are rejected because no human lives long enough to experience them under any key.

max_age default 90, polar bodies flagged not clamped, converse rule respected

1 min read

Arc directions: Naibod, lunar arc, chart-ruler arc as standalone methods

Some practitioners prefer the simpler arc directions to true primary directions.

The API ships three arc-direction endpoints alongside the canonical primary directions endpoint.

Solar arc Naibod advances every body in the chart by the same rate: 0.9856473° per year.

It's the symbolic 1°/year method's serious cousin.

Lunar arc advances every body by the progressed Moon's daily motion scaled to ~0.99°/year, useful when the Moon is the chart's most prominent significator.

Chart-ruler arc advances every body by the personalized rate of the Ascendant lord's daily motion.

Each endpoint takes the same input (natal data + target age or target date) and returns the directed positions of all 10 planets plus the four angles.

You can then run aspect detection against the natal positions to find the hits.

Arc directions are faster to compute than full primary directions and are the right tool when you need a single forecasting rate, not the full diurnal-arc rotation.

Solar arc Naibod, lunar arc, chart-ruler arc all available as standalone endpoints

1 min read

Validation: how do we know the math is right?

Every commit runs against three published validation cases from Gansten and Robert Hand.

Princess Diana (1961-07-01, 19:45 BST, Sandringham 52°50'N 0°30'E): MC direct to Mars/Pluto square reaches exact in 1997 under Naibod mundo (death: 1997-08-31).

John F.

Kennedy (1917-05-29, 15:00 EST, Brookline MA): Ascendant direct to Saturn mundo reaches exact around 1963 under Naibod (death: 1963-11-22).

Adolf Hitler (1889-04-20, 18:30 LMT, Braunau): MC direct to Saturn zodiacal reaches exact in April 1945 under Naibod, the standard ephemeris benchmark because Morin, Choisnard, and Solar Fire all publish the same arc to three decimals.

Our endpoint matches Morinus (the open-source Placidus semi-arc reference implementation) and Solar Fire v9 to within ±0.01° arc and ±2 days.

Cross-check tolerance is published in the docs.

The endpoint also surfaces calculation_method and key_used in metadata so you can audit which method produced each hit.

Matches Morinus and Solar Fire v9 within ±0.01° arc, ±2 days

1 min read

Use Cases

Traditional Astrologers

Generate Hellenistic and medieval-style life forecasts with mundo and zodiacal hits, dignity-aware significator selection, and Naibod key as default

Astrology SaaS for Advanced Users

Add primary directions to your platform without writing the polar-elevation math yourself: one endpoint, JSON response, sub-300ms

AI Astrology Chatbots

Time-lord depth for agent conversations: GPT and Claude can request directions per significator, per key, per age range via MCP

Content Publishers

Write event-timing articles backed by reproducible arcs: same numbers Morinus and Solar Fire produce, but as a REST call

Forecasting Schools and Research

Compare keys side by side: Ptolemy vs Naibod vs true solar vs lunar arc on the same chart, all in one response

Historical Astrology Tools

Validate published hits from Gansten, Hand, Lilly, and Morin against your own data set with exact dates and named promissor and significator

Technical Specifications

Endpoint	POST /api/v3/directions/primary (plus /directions/arc/naibod, /directions/arc/lunar, /directions/arc/chart-ruler)
Method	Placidus semi-arc 3D per Gansten (2009)
Ephemeris	Swiss Ephemeris with SEFLG_SWIEPH \| SEFLG_EQUATORIAL flag
Levels	mundo, zodiaco, both
Time Keys	ptolemy (1°/y), naibod (0.9856473°/y, default), true_solar, lunar, chart_ruler
Significators	Ascendant, Medium Coeli, Sun, Moon, Pars Fortunae (configurable)
Promissors	All 7 classical planets, configurable, plus optional fixed stars (Regulus, Spica, Algol, Antares)
Aspects	Conjunction, sextile, square, trine, opposition (Ptolemaic set)
Direction Types	Direct and converse, include_converse=true by default
Max Age	Default 90 years, configurable up to 100; arcs over 100° rejected
Arc Tolerance	±0.001° vs Morinus / Solar Fire v9
Date Tolerance	±2 days on resulting calendar date
Polar Handling	Bodies above \|φ\| > 66° flagged polar_undefined, not clamped
Optional Add-Ons	include_antiscia, include_fixed_stars (Regulus, Spica, Algol, Antares)
P95 Response Time	<300ms

Why the Primary Directions API Beats 2D Shortcut Tools

Feature	Astrology API	Others
Method	Placidus semi-arc 3D per Gansten (2009)	2D ecliptic shortcut, no polar elevation step
Pole of Significator	Computed per body via tan(pole) = sin(W) · tan(φ)	Uses geographic latitude (the most common bug per Hand)
Levels	Mundo and zodiacal both, returned as separate hit lists	Zodiacal only with latitude
Time Keys	Ptolemy, Naibod, true solar, lunar arc, chart-ruler arc (5 keys)	1 key, usually Ptolemy 1°/year
Converse Motion	Included by default, significator's pole still governs	Not supported or computed incorrectly
Polar Latitude Handling	Bodies flagged polar_undefined, not silently clamped	Crashes or returns false values
Sect-Awareness	Day/night significator sets respected	Not implemented
Validation	Matches Morinus and Solar Fire v9 within ±0.01° arc, ±2 days	No published reference set
P95 Response Time	<300ms	1 to 3 seconds, or batch-only
Price	$11/month for 1,000 requests	$199 desktop license (Solar Fire) or $89 (Janus)

Related Predictive Astrology APIs

Directions Hub

All direction methods in one suite: primary, secondary, solar arc, tertiary

Solar Return API

Annual birthday chart, precessed or tropical, paired with primary directions for year forecasts

Profections API

Hellenistic time-lord technique: annual, monthly, daily, biwheel with LOY

Zodiacal Releasing

L1 to L4 periods from Spirit and Fortune with peak detection

Firdaria API

Persian major and minor time-lord periods, sect-aware

Transit API

Current planetary aspects to natal chart, the day-level companion to primary directions

References & Standards

Swiss Ephemeris (DE431-based) — astronomical calculations source
NASA JPL Planetary Ephemerides — underlying ephemeris dataset
International Astronomical Union (IAU) — body designation and nomenclature standards
IANA Time Zone Database — timezone & DST resolution

Simple, Transparent Pricing

Start free, scale as you grow. No hidden fees, no surprises.

Always Free

Start Free

Perfect for learning, testing, and small personal projects

50 API calls/month

Basic natal charts

5 house systems

Community support

Pro

$11/month

For small apps and personal projects

All basic endpoints
12 house systems
Email support

Best Value

Pro Plus

$21/month

For growing apps and medium traffic

All enhanced endpoints
18 house systems
AI interpretations
Priority email support

Ultra

$37/month

For professional astrology applications

Credit math ↓

All premium endpoints
23 house systems
Advanced AI interpretations
Priority support

High Volume Plans

For enterprise-scale applications

Business

$99/month

For high-volume applications

Credit math ↓

ALL endpoints
White-label ready
Custom AI fine-tuning
Phone support

UNLIMITED

Enterprise

$399+per month

Unlimited requests with dedicated infrastructure

Dedicated server infrastructure
Sub-300ms guaranteed
24/7 dedicated support
99.99% uptime SLA

All plans include comprehensive documentation and SDKs

Questions? Talk to our team

Primary Directions API FAQ

The questions astrologers and developers actually ask

Build a Full Predictive Astrology Stack

Pair the Primary Directions API with the rest of the timing suite. Add

Directions hub Solar Return Profections Zodiacal Releasing Firdaria Transit API

Ship Primary Directions in One

Gansten's canonical method. Naibod, Ptolemy, true solar, lunar arc, and chart-ruler arc keys. Direct and converse motion. Swiss Ephemeris precision. Sub-300ms.

Start Free Now Read API Docs

50 free requests per month, forever

30-day money-back guarantee

No setup fees, no credit card to start

Primary Directions Done the Gansten Way

Most APIs Skip the Math That Makes Primary Directions Work

What the Primary Directions API Returns

Primary Directions API at a Glance

Primary Directions API Feature List

Placidus Semi-Arc 3D Method

Mundo Directions

Zodiacal Directions

Naibod Key (Default)

Ptolemy Key

True Solar Arc Key

Lunar Arc Key

Chart-Ruler Arc Key

Direct and Converse Motion

Configurable Significators

Optional Fixed Stars and Antiscia

Polar-Latitude Edge Case Handling

Primary Directions API: Placidus Semi-Arc 3D, Gansten Method

What is Gansten's Placidus semi-arc 3D method?

Mundo vs zodiacal: which one should you direct?

Which time key: Ptolemy, Naibod, true solar, lunar, or chart-ruler arc?

Direct and converse motion, polar handling, life-span cap

Arc directions: Naibod, lunar arc, chart-ruler arc as standalone methods

Validation: how do we know the math is right?

Use Cases

Traditional Astrologers

Astrology SaaS for Advanced Users

AI Astrology Chatbots

Content Publishers

Forecasting Schools and Research

Historical Astrology Tools

Technical Specifications

Why the Primary Directions API Beats 2D Shortcut Tools

Related Predictive Astrology APIs

Directions Hub

Solar Return API

Profections API

Zodiacal Releasing

Firdaria API

Transit API

References & Standards

Simple, Transparent Pricing

Always Free

Pro

Pro Plus

Ultra

High Volume Plans

Business

Enterprise

Primary Directions API FAQ

What is Gansten's 3D Placidus semi-arc method?

What's the difference between primary directions and arc directions?

Which key does the API use: Ptolemy, Naibod, or both?

How accurate are the calculations?

Does the API support mundo and zodiacal directions?

How does this compare to Solar Fire, Janus, and Morinus?

How much does it cost?

How do I direct the Moon vs an angle?

What is converse motion?

How does the API handle high-latitude births and circumpolar bodies?

Can I get directions for fixed stars like Regulus or Algol?

What aspects are supported?

Is the endpoint sect-aware?

What's the response format?

Can I run primary directions from an AI agent like Claude or GPT?

What programming languages can I call the API from?

How does primary directions fit alongside profections, Firdaria, and Zodiacal Releasing?

Build a Full Predictive Astrology Stack

Ship Primary Directions in One

Most APIs Skip the Math That Makes Primary Directions Work

What the Primary Directions API Returns

Primary Directions API at a Glance

Primary Directions API Feature List

Placidus Semi-Arc 3D Method

Mundo Directions

Zodiacal Directions

Naibod Key (Default)

Ptolemy Key

True Solar Arc Key

Lunar Arc Key