What is Ebertin Cosmobiology?

Cosmobiology is a 20th-century astrological method developed by Reinhold Ebertin in Germany. It strips chart interpretation down to hard aspects (conjunction, opposition, square, semi-square, sesquiquadrate) read on a 22.5° dial — the 4th harmonic of the zodiac. Midpoints and the graphic ephemeris are central tools. Cosmobiology emphasizes timing and event prediction over psychological reading. The graphic-ephemeris endpoint gives you the visualization Cosmobiology practitioners have used since Ebertin's Combination of Stellar Influences (1940).

Why is the 4th harmonic 22.5° the standard?

360° divided by 16 equals 22.5°. The 4th harmonic surfaces every hard aspect: conjunction (0°), semi-square (45°), square (90°), sesquiquadrate (135°), and opposition (180°) all collapse onto the same 22.5° grid because each is a multiple of 22.5°. Soft aspects (trine, sextile) do not. That makes the 22.5° dial a hard-aspect detector — which is why Cosmobiology adopted it as the de facto standard for timing work. graphic-ephemeris defaults to harmonic=4 for this reason.

Are SVG layers named for downstream styling?

Yes. Every /render/* endpoint groups SVG elements into named layers: g id='axes', g id='aspects', g id='planets' on the wheel; g id='bars', g id='ticks', g id='axis' on transit gantt; g id='planet-sun', g id='planet-moon', etc. on graphic-ephemeris. Your CSS or downstream SVG processor can target any layer by id without parsing geometry — re-color planets, hide the aspect layer, restyle ticks. The naming convention stays stable across versions.

What chart themes are available?

Four presets: minimal (clean light), minimal-dark (clean dark paper), astrocom (light version of the astro.com look), and astrocom-dark (dark version of the astro.com look). Underneath, four Kerykeion native CSS themes also work: light, dark, dark-high-contrast, classic. Pass theme=astrocom-dark for the most popular dark professional look. Each preset layers on top of a base Kerykeion CSS theme, so paper colors and zodiac sectors inherit cleanly.

Can I get an Astrocom-style chart?

Yes — set theme=astrocom (light) or theme=astrocom-dark. This combines four patches at once: axis_stroke_width=3.0 for thick AC/MC/DC/IC lines, axes_labels_position='outside' for labels just past the wheel, house_numbers_position='center' for the inner-ring house number layout, and a unified axis_color (#444444 light, #6b7280 dark). The output mimics the astro.com (Astrodienst) reference chart that traditional astrologers have read for 30+ years.

How do I customize axis thickness?

Pass axis_stroke_width as a float. 1.0 is the default (Kerykeion's pre-patch behavior). 3.0 matches the astrocom preset and the astro.com reference. 5.0+ works for wall-poster output. The parameter only affects the four axis cusps (AC at index 0, IC at 3, DC at 6, MC at 9). Other house cusps stay at 1px dashed at 0.4 opacity. Axis lines render solid at 0.9 opacity when this parameter is set.

Can I hide specific planets from aspect lines?

Yes — pass hide_points_in_aspects as an array of point names, e.g. ['Chiron','Mean_Lilith','Mean_South_Node']. These points stay visible on the wheel but the post-processor strips them from every aspect line in the SVG and removes their row from the aspect grid. Useful for embeds where you want a clean aspect view without removing minor bodies from the chart entirely. The post-processor runs after Kerykeion's makeTemplate(), so timing is consistent.

Does the API render Part of Fortune?

Yes. Add 'part_of_fortune' to active_points and three things happen: the day/night formula computes the position (ASC + Moon - Sun for day charts, ASC + Sun - Moon for night), the circled cross glyph renders on the wheel via the new Part_of_Fortune symbol in the SVG defs, and a Part of Fortune row appears in the aspect grid. We compute Part of Fortune aspects ourselves because upstream Kerykeion does not know the body exists. Works for natal and external-natal chart types today.

Do you support Uranian / Hamburg School planets?

Yes — all eight Uranian hypotheticals render natively: Cupido, Hades, Zeus, Kronos, Apollon, Admetos, Vulcanus, Poseidon. Add the names you want to active_points and the settings_builder injects each one's glyph and color config. They show up on the wheel and in the aspect grid like any other body. Combine with hide_points_in_aspects to draw the glyphs without the aspect noise, which matches the Hamburg School notation style.

Can I render synastry, transit, and composite charts?

Yes — one endpoint, four chart types: Natal, Synastry, Transit, Composite. The theme system applies to all of them, so theme=astrocom-dark gives you a dark astrocom-style synastry chart with both subjects' names in the dual-chart heading. Synastry and transit secondary subjects also get the patched house numbers and (when configured) their own Part of Fortune glyph. Cross-subject Part of Fortune aspects are on the roadmap.

Why did you vendor Kerykeion v4.26.3 instead of just importing it?

Importing pip Kerykeion meant we could not change axis behavior, add Part of Fortune, or patch the aspect logic without forking. We copied Kerykeion v4.26.3 into app/vendor/kerykeion_charts/, kept import paths compatible, and added a PATCHES.md that tracks every change. Now upstream upgrades are a deliberate code review instead of a silent breaking change in production. Every patch has a numbered tag (PATCH-01 through PATCH-04 plus PATCH-PartOfFortune) and a matching inline comment in the source.

Where do house numbers go with house_numbers_position='center'?

House numbers render in an inner ring at 78% of the wheel radius (r * 0.78), using 10px font with 0.7 fill-opacity. This is the astro.com layout. Default ('near_cusp' or null) keeps them at the original dropin offset next to each cusp with 14px font and 0.6 fill-opacity. For synastry and transit charts, the same shrink applies to the secondary subject's numbers — the transit-specific fill-opacity logic (0 for transit, 0.4 otherwise) is preserved.

What does hide_axes_visually do?

Pass an array of axis names (e.g. ['IC','DC']) and those axis lines are removed from the SVG, while the underlying calculations stay intact. The angles are still in the chart data, so aspect calculations and house positions stay correct — only the visible line is gone. Useful for minimal embeds where you want to show planets and signs without the cross of cardinal axes. This is currently a stub-level post-processor; full per-axis control is on the roadmap.

How fast does rendering take?

Typical render time stays under 500ms, worst case under 1 second. The vendored Kerykeion code path adds minimal overhead — the patches are mostly conditional branches in existing draw functions plus one post-processor pass on the SVG string. Cold-start time depends on Swiss Ephemeris file loading. Edge caching covers identical requests, so repeated chart generation for the same birth data returns near-instantly.

Which output formats do I get?

SVG is the primary output — everything the renderer does is SVG-native. PNG, JPEG, WebP, and PDF are available through format conversion endpoints. SVG is what you want for web embeds because it scales without quality loss and is small. Use PNG or JPEG when you need email-client compatibility (Outlook). PDF preserves vector quality for print. WebP is roughly 30% smaller than PNG for the same visual quality.

Can I override theme settings per request?

Yes — pass a custom_settings dict to override any chart setting on top of the theme. The merge is shallow: theme defaults load first, your custom_settings dict overrides on top, the result feeds into Kerykeion. You can also pass individual patch parameters (axis_stroke_width, axes_labels_position, etc.) directly — these always win over theme defaults. A theme is a starting point, not a constraint.

How much does Chart Rendering API cost?

Chart rendering costs 10 credits per request. The Ultra plan starts at $37/month for 55,000 credits (about 5,500 charts). Business plan is $99/month for 220,000 credits (about 22,000 charts). Free tier does not include chart rendering — only data endpoints. Enterprise plans get dedicated infrastructure and unlimited generation.

What house systems are supported?

23 house systems work with every theme and every chart type: Placidus, Whole Sign, Equal House, Koch, Regiomontanus, Campanus, Morinus, Porphyry, Topocentric, Alcabitius, Krusinski, Sripati, and 11 more. House system choice is independent from theme — you can render a Whole Sign chart in the astrocom-dark theme and the cusps draw correctly. Calculations use Swiss Ephemeris (NASA JPL data).

How accurate are the underlying calculations?

Sub-arcsecond accuracy for every planet, asteroid, and hypothetical body. The renderer is a thin layer on top of Swiss Ephemeris, which uses NASA JPL ephemeris data — the same source professional astronomy software relies on. Theme and customization parameters only affect visual output; the math is identical regardless of which theme you pick.

Are there timing wheels (age-bands, bi-wheel)?

Yes — SVG timing wheels live at /svg/timing/* as separate endpoints. The age-bands wheel renders life-phase rings around a natal chart. The bi-wheel renderer overlays one chart on another (e.g. transit over natal) with both rings visible. They share the same vendored Kerykeion core as the standard chart_svg endpoint, so theme presets and patch parameters apply.

How do I integrate this with my app?

It is a REST API. Send birth data (date, time, location), plus theme and any customization params, get an SVG string back. Works with any language — curl, JavaScript, Python, Ruby, PHP, Go. For web, drop the SVG into the page directly. For mobile apps, request PNG or WebP through the format conversion endpoints. Same auth, same rate limits, same credit model across all chart types.

Is there rate limiting on chart generation?

Rate limits depend on plan. Ultra (55,000 credits/month) covers most independent platforms. Business (220,000 credits) suits scaling apps. Enterprise plans run on dedicated infrastructure with no monthly cap. At 10 credits per chart, Ultra gives you ~5,500 charts/month and Business gives you ~22,000 — the cap is the credit pool, not a per-second rate limit.

Customizable SVG Charts

Chart Rendering API: Astrocom-Grade SVG, Your Rules

We vendored Kerykeion v4.26.3 so we can patch it.

The result: 3 theme presets, an Astrocom-style preset, 10+ chart parameters, Part of Fortune, Uranian planets, and natal/synastry/transit/composite from one endpoint.

View Demo

Gantt

Transit Timing Bars

22.5°

Ebertin 4th Harmonic

Astrocom

Theme Presets

10+

Custom Params

2.1M+ charts rendered monthly

Used by 750+ platforms worldwide

Swiss Ephemeris precision guaranteed

Forecasting dashboards need pro-grade timing views — Gantt bars and graphic ephemeris — not just natal wheels
Off-the-shelf Kerykeion output is fixed: same axes, same fonts, same look on every site
No way to mimic the Astrocom (Astrodienst) aesthetic that traditional astrologers expect
Aspect lines pile up — and you cannot hide specific points without removing them from the wheel
Part of Fortune is missing from upstream rendering (no glyph, no aspect row)
Axis lines (AC, MC, DC, IC) all render the same — no way to thicken them or change label position
Hamburg School and Uranian astrologers cannot show their hypothetical planets
House numbers stuck in one place; no inner-ring layout option
Cosmobiology workflows need the Ebertin 4th-harmonic grid; most APIs do not ship one

Transform with

/api/v3/render/* is the consolidated namespace — chart wheels, transit gantt, graphic ephemeris all live as siblings
/render/transit-gantt: horizontal-bar visualization of aspect timing windows for forecasting dashboards
/render/graphic-ephemeris: Ebertin-style 4th-harmonic 22.5° grid plotting planets as continuous lines
Named SVG layers (g id='axes', g id='aspects', g id='planets') for downstream CSS styling
3 theme presets: minimal, minimal-dark, astrocom-dark — pick a look in one parameter
Astrocom preset: thicker axes, outside AC/MC/DC/IC labels, centered house numbers — out of the box
10+ chart params: axis_stroke_width, axes_labels_position, house_numbers_position, axis_color, and more
hide_points_in_aspects: drop selected planets from aspect lines while keeping them on the wheel
Part of Fortune + 8 Uranian hypotheticals render server-side
Natal, synastry, transit, composite — same chart endpoint, same theme system

Chart Rendering Performance

Vendored Kerykeion v4.26.3 with our customization layer

Theme Presets

10+

Customization Params

SVG (post-processed)

Primary Output

<500ms

Render Time

Wheel, Transit Gantt, Graphic Ephemeris

Render Endpoints

2.1M+

Monthly Renderings

Customizable SVG, From Theme Down to Single Axis

3 presets, 10+ params, Astrocom-grade output

Transit Gantt SVG

/render/transit-gantt draws horizontal bars for aspect timing windows. Rows are planet pairs, columns are dates, exact-hit ticks inside each bar.

Endpoint: /api/v3/render/transit-gantt — color-coded by aspect type, named SVG layers

Graphic Ephemeris SVG

/render/graphic-ephemeris plots planets as continuous lines on the Ebertin 4th-harmonic 22.5° grid. Line meetings mark hard aspects by Cosmobiology logic.

Endpoint: /api/v3/render/graphic-ephemeris — harmonic 1/2/4/8/16, default 12-month window

Ebertin 4th-Harmonic Standard

22.5° grid is the de facto Cosmobiology standard since the 1940s. We ship it as the default harmonic on graphic-ephemeris.

harmonic=4 default; switchable to 1, 2, 8, 16 per request

Named SVG Layers

Every render output groups elements into named SVG layers (g id='axes', 'aspects', 'planets', 'bars', 'ticks') so downstream CSS can re-style without parsing geometry.

Stable id naming convention across all /render/* endpoints

/render/* Namespace

One namespace for visualizations: chart wheels, transit gantt, graphic ephemeris. Old /svg/timing/* paths still work for backward compatibility.

Consolidated under /api/v3/render/* — legacy /svg/timing/* aliased

Astrocom Theme Preset

One parameter (theme=astrocom) gives you the astro.com chart look — thick axes, outside AC/MC/DC/IC labels, centered house numbers, unified axis color.

Combines PATCH-01, PATCH-02, PATCH-03, PATCH-04 with #444444 axis color

Astrocom-Dark Theme

Dark counterpart of Astrocom — same structural patches, dark paper, unified axis color tuned for dark UIs.

axis_color=#6b7280, layers on Kerykeion dark.css

Minimal Theme

Clean light theme with muted aspect lines and plain zodiac sectors — for embeds that should not fight the page.

Layers on classic.css, no structural patches applied

Minimal-Dark Theme

Same minimal look on dark paper — works for dark UI without writing extra CSS.

Inherits dark.css paper and zodiac sector colors

axis_stroke_width Parameter

Control how thick the AC/MC/DC/IC axis cusps render. 1.0 default, 3.0 mimics astro.com, 5.0 for wall posters.

Float — applies only to axis cusps (indices 0, 3, 6, 9), solid line at 0.9 opacity

axes_labels_position Parameter

Place AC/MC/DC/IC labels outside the wheel (bold), in a small inner ring (medium weight), or hide them entirely.

Accepts 'outside' | 'center' | null — coordinate math reuses cusp offset formula

house_numbers_position Parameter

Render house numbers in an inner ring at 78% radius (astro.com style) or near each cusp (default).

Accepts 'center' | 'near_cusp' — also applies to synastry/transit secondary subject

Part of Fortune Glyph

Add 'part_of_fortune' to active_points — the circled cross glyph renders on the wheel and a Part of Fortune row shows in the aspect grid.

Day/night formula, id=23 to keep upstream indexed accesses stable

hide_points_in_aspects

Pass an array of point names to drop them from aspect lines and the aspect grid — without removing the glyphs from the wheel.

Post-processor on the SVG string — runs after Kerykeion makeTemplate()

hide_axes_visually

Keep AC/MC/DC/IC in the calculation but hide the lines from the SVG. Useful for clean embed views.

Stub-level post-processor — accepts axis name array

Hypothetical Planets

8 Uranian / Hamburg School hypotheticals — Cupido, Hades, Zeus, Kronos, Apollon, Admetos, Vulcanus, Poseidon — render with their own glyphs.

Add to active_points; settings_builder injects glyph + color config

Dual-Chart Heading

Synastry and transit charts keep their dual-subject heading across the renderer refactor — both names, both birth dates render above the wheel.

Preserved through ChartRenderer facade in app/services/chart_renderer/renderer.py

Composite Chart Type

Midpoint composite charts render through the same endpoint with the same theme system.

chart_type='Composite' on the unified ChartRenderer facade

Swiss Ephemeris Precision

NASA JPL ephemeris data drives every planetary position regardless of theme or chart type.

Sub-arcsecond accuracy for all celestial bodies

23 House Systems

Placidus, Whole Sign, Equal House, Koch, Regiomontanus, Campanus, Morinus, Porphyry, Topocentric, and 14 more.

House system selection independent from theme

Custom Settings Override

Pass a custom_settings dict to override any chart field per request — colors, glyph colors, paper colors, zodiac colors.

Merged on top of theme defaults; caller wins

What is Chart Rendering API? The Vendored-Kerykeion Story

3 theme presets, 10+ customization params, Astrocom-grade output, Part of Fortune, Uranian planets

Chart Rendering API turns birth data into a customizable SVG astrology chart. We vendored Kerykeion v4.26.3 into our own codebase so we could patch it — that gave us thicker axes, outside-ring axis labels, centered house numbers, a Part of Fortune glyph, hypothetical planet support, and a post-processor that can hide selected points from aspect lines. You get three theme presets out of the box (minimal, minimal-dark, astrocom-dark), 10+ chart parameters, and one endpoint that handles natal, synastry, transit, and composite charts. Render time stays under 500ms.

Why did we vendor Kerykeion v4.26.3 instead of importing it?

Kerykeion is a strong open-source chart library, but the upstream renderer is locked down: fixed axis widths, no Part of Fortune, no hooks for hiding points from aspect lines, and no path for Hamburg School hypothetical planets.

We copied the relevant modules into app/vendor/kerykeion_charts/ at version 4.26.3, kept the import surface compatible, and added a PATCHES.md that tracks every change.

Four numbered patches (PATCH-01 through PATCH-04) plus a Part of Fortune injection cover the new parameters.

Two themes that ship with the upstream library (light, dark, dark-high-contrast, classic) still work as base layers.

Our presets layer on top of those base CSS variables, so dark-mode paper colors, zodiac sector colors, and glyph colors inherit cleanly.

The vendor approach means every upstream upgrade is a code review — not a surprise breaking change in production.

Vendored Kerykeion v4.26.3 — we own the patch line

1 min read

Which theme should I pick: minimal, minimal-dark, or astrocom-dark?

Three presets cover most cases.

Minimal is a clean light theme: muted aspect lines, plain zodiac sectors, light paper.

Use it for blog embeds, social cards, and apps that want a chart that does not fight the rest of the page.

Minimal-dark inverts the paper to dark grey, keeps the aspect colors readable, and works for dark UIs.

Astrocom-dark is the dark counterpart of the Astrocom preset: thicker axes, outside-ring AC/MC/DC/IC labels, centered house numbers, unified axis color (#6b7280) — basically the Astrodienst chart look in a dark wrapper.

Pass theme=astrocom to get the light version, theme=astrocom-dark for dark, theme=minimal for a clean light look, or theme=minimal-dark for the same on dark.

You can still override any of the underlying parameters per request, so a theme is a starting point — not a cage.

3 presets: minimal, minimal-dark, astrocom-dark — plus astrocom (light)

1 min read

What is the Astrocom preset and why does it matter?

Astrocom is the look you see on astro.com — the Astrodienst chart that professional astrologers have been reading since the 90s.

It is the de facto reference style for the Western tradition: thick black axis lines, AC/MC/DC/IC labels just outside the wheel, house numbers in an inner ring instead of next to the cusps, and a single neutral axis color so the four cardinal directions do not fight each other.

The astrocom preset combines PATCH-01 (axis_stroke_width=3.0), PATCH-02 (axes_labels_position='outside'), PATCH-03 (house_numbers_position='center'), and PATCH-04 (axis_color='#444444' for light, '#6b7280' for dark).

Set theme=astrocom and you get all four at once.

For platforms targeting traditional astrologers, this preset alone is often the reason teams switch.

The classic Kerykeion theme has per-axis colors (orange/black/blue/red) which clashes with a more reserved layout — astrocom unifies them.

Astrocom preset = astro.com reference look in one parameter

1 min read

How do per-element parameters work?

Five parameters let you override the preset on a single request.

axis_stroke_width takes a float — 1.0 is default, 3.0 mimics astro.com, 5.0 is wall-poster thick.

axes_labels_position accepts 'outside' (just past the wheel, bold), 'center' (small inner ring, medium weight), or null (no axis labels — Kerykeion's pre-patch behavior).

house_numbers_position takes 'center' (small inner ring at 78% radius, 10px font, 0.7 opacity) or 'near_cusp' (default, 14px, next to each cusp).

hide_points_in_aspects takes an array of point names: pass ['Chiron','Lilith'] and Chiron and Lilith stay on the wheel but vanish from every aspect line and the aspect grid row.

hide_axes_visually takes an array of axis names: the AC stays in the calculation, but no line is drawn — useful for embeds where you want a clean wheel.

axis_color overrides the per-axis CSS variables with one unified color.

5 patch parameters: axis_stroke_width, axes_labels_position, house_numbers_position, hide_points_in_aspects, hide_axes_visually

1 min read

What is the /render/transit-gantt endpoint?

/api/v3/render/transit-gantt is an SVG renderer for aspect timing windows.

Instead of a wheel, you get a horizontal-bar chart: rows are planet pairs (e.g.

transit Saturn to natal Sun), columns are dates, and each bar marks the window when the aspect is in orb.

Exact-hit dates show as vertical ticks inside each bar.

The output is a forecasting dashboard view that astrologers and timing apps need — when does this transit start, when does it peak, when does it end.

Bars are color-coded by aspect type (conjunction, square, opposition, trine, sextile) and the SVG ships with named layers (g id='bars', g id='ticks', g id='axis') so downstream CSS can re-style without parsing geometry.

Spec lives at docs/SPECS/06_timing_visualizations.md §A, renderer at app/services/render/transit_gantt.py.

Time range, included aspects, and orb tolerances are request parameters.

/render/transit-gantt — horizontal-bar SVG for aspect timing windows

1 min read

What is the /render/graphic-ephemeris endpoint?

/api/v3/render/graphic-ephemeris is the Ebertin-style 4th-harmonic graphic ephemeris — a Cosmobiology staple since the 1940s.

The X-axis is time.

The Y-axis is the 22.5° grid (360° / 16 — the 4th harmonic, or fourth division of the 22.5° basic dial).

Each planet plots as a continuous line that wraps when it crosses 22.5°.

When two lines meet on the grid, that is a hard aspect by 4th-harmonic logic: conjunction, opposition, square, or semi-square.

Cosmobiology practitioners read these meetings as event dates.

Harmonic options: 1 (raw longitude), 2, 4 (Ebertin default), 8, or 16.

Default time window is 12 months, configurable.

Output is SVG with named layers (g id='planet-sun', g id='planet-moon', etc.) so each planet line is selectable by CSS.

Spec: docs/SPECS/06_timing_visualizations.md §B.

Renderer: app/services/render/graphic_ephemeris.py.

/render/graphic-ephemeris — Ebertin 4th-harmonic 22.5° grid

1 min read

Use Cases

Traditional Astrologer Platforms

theme=astrocom delivers the astro.com chart look professionals already trust

Modern Dark-Mode Apps

theme=minimal-dark or astrocom-dark match dark UI without extra CSS work

Hellenistic Charts with Part of Fortune

Add 'part_of_fortune' to active_points — glyph and aspect row render automatically

Uranian / Hamburg School

8 hypothetical planets (Cupido through Poseidon) render with their own glyphs

Aspect-Focused Embeds

hide_points_in_aspects drops minor bodies from lines while keeping the wheel intact

Synastry, Transit, Composite

One endpoint, same theme system, dual-chart heading preserved across types

Technical Specifications

Render Namespace	/api/v3/render/* (chart, transit-gantt, graphic-ephemeris)
Transit Gantt Time Range	Default 12 months; configurable start/end
Graphic Ephemeris Harmonic	1, 2, 4 (Ebertin default), 8, or 16
SVG Layer Naming	g id='axes' \| 'aspects' \| 'planets' \| 'bars' \| 'ticks'
Renderer Base	Vendored Kerykeion v4.26.3 + 4 numbered patches
Theme Presets	minimal, minimal-dark, astrocom, astrocom-dark
Native Kerykeion Themes	light, dark, dark-high-contrast, classic
axis_stroke_width	Float — 1.0 default, 3.0 astrocom, up to 5.0
axes_labels_position	outside \| center \| null (no labels)
house_numbers_position	center (inner ring at r*0.78) \| near_cusp (default)
axis_color	Hex string — overrides per-axis CSS variables
hide_points_in_aspects	Array of point names — post-processor strips them from aspect lines
hide_axes_visually	Array of axis names — kept in calc, dropped from SVG
active_points	Includes part_of_fortune + 8 Uranian hypotheticals
Chart Types	Natal, Synastry, Transit, Composite (one endpoint)
Output Formats	SVG primary; PNG, JPEG, WebP, PDF via conversion
Render Time	<500ms typical, <1s worst case
House Systems	23 supported (Placidus, Whole Sign, Koch, etc.)
Calculation Precision	Swiss Ephemeris (NASA JPL data)
Custom Settings Override	custom_settings dict — any field, per request

Vendored Kerykeion + Patches vs Stock Kerykeion vs Closed Competitors

Feature	Astrology API	Others
Visualization Coverage	Wheel + transit gantt + graphic ephemeris (3 render endpoints)	Natal wheels only
Source Base	Vendored Kerykeion v4.26.3 — we own the patch line	Stock pip install OR closed SDK
Astrocom-Style Output	theme=astrocom — one parameter	Not available; locked chart style
Theme Presets	minimal, minimal-dark, astrocom, astrocom-dark	Fixed look or 1-2 themes
Axis Stroke Width	Float param, 1.0 to 5.0+	Hardcoded 1px
House Numbers Position	center \| near_cusp	Near cusp only
Hide Points from Aspects	hide_points_in_aspects array — post-processor	All-or-nothing; remove from chart entirely
Part of Fortune	Formula + glyph + aspect grid row	Not supported (Kerykeion); varies elsewhere
Hypothetical Planets	8 Uranian (Cupido through Poseidon) native	Rarely supported
Chart Types	Natal, Synastry, Transit, Composite — one endpoint	Often separate endpoints or libraries
Upstream Upgrade Path	Code review every bump — PATCHES.md tracked	Silent breaking changes on pip upgrade
Render Time	<500ms typical	1-3 seconds common

Related Astrology APIs

Transit Gantt SVG

Horizontal-bar visualization of aspect timing windows

Graphic Ephemeris SVG

Ebertin-style 4th-harmonic 22.5° grid

Natal API

Birth chart calculations powering the chart renderer

Part of Fortune

Hellenistic lot — formula, glyph, aspect row

Hypothetical Planets

Hamburg School / Uranian — 8 hypotheticals native

Synastry API

Relationship charts with the same theme system

Composite API

Midpoint composite charts for couples

Timing API

Age-bands and bi-wheel timing SVGs

Transit API

Live transits over a natal wheel

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

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5 house systems

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All basic endpoints
12 house systems
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$21/month

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All enhanced endpoints
18 house systems
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Frequently Asked Questions about Chart Rendering API

Themes, patches, Part of Fortune, hypothetical planets, and everything in between

Related Astrology APIs

Chart SVG API works best alongside the rest of the stack. Add

transit gantt SVG graphic ephemeris SVG birth chart calculations Part of Fortune hypothetical planets synastry charts composite charts timing wheels live transits

Three SVG Renderers, One Namespace

Chart wheels, transit gantt bars, and graphic ephemeris on the Ebertin 4th-harmonic 22.5° grid — all under /api/v3/render/*. Astrocom themes, named SVG layers, Part of Fortune, Uranian planets.

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Transit gantt + graphic ephemeris SVG

Ebertin 4th-harmonic 22.5° grid

Named SVG layers for CSS styling

<500ms render time

Available on Ultra plan and above

Chart Rendering API: Astrocom-Grade SVG, Your Rules

Natal Wheels Alone Do Not Power Forecasting Dashboards

One Render Namespace: Wheels, Gantt Bars, Graphic Ephemeris

Chart Rendering Performance

Customizable SVG, From Theme Down to Single Axis

Transit Gantt SVG

Graphic Ephemeris SVG

Ebertin 4th-Harmonic Standard

Named SVG Layers

/render/* Namespace

Astrocom Theme Preset

Astrocom-Dark Theme

Minimal Theme

Minimal-Dark Theme

axis_stroke_width Parameter

axes_labels_position Parameter

house_numbers_position Parameter

Part of Fortune Glyph

hide_points_in_aspects

hide_axes_visually

Hypothetical Planets

Dual-Chart Heading

Composite Chart Type

Swiss Ephemeris Precision

23 House Systems

Custom Settings Override

What is Chart Rendering API? The Vendored-Kerykeion Story

Why did we vendor Kerykeion v4.26.3 instead of importing it?

Which theme should I pick: minimal, minimal-dark, or astrocom-dark?

What is the Astrocom preset and why does it matter?

How do per-element parameters work?

What is the /render/transit-gantt endpoint?

What is the /render/graphic-ephemeris endpoint?

Use Cases

Traditional Astrologer Platforms

Modern Dark-Mode Apps

Hellenistic Charts with Part of Fortune

Uranian / Hamburg School

Aspect-Focused Embeds

Synastry, Transit, Composite

Technical Specifications

Vendored Kerykeion + Patches vs Stock Kerykeion vs Closed Competitors

Related Astrology APIs

Transit Gantt SVG

Graphic Ephemeris SVG

Natal API

Part of Fortune

Hypothetical Planets

Synastry API

Composite API

Timing API

Transit API

References & Standards

Simple, Transparent Pricing

Always Free

Pro

Pro Plus

Ultra

High Volume Plans

Business

Enterprise

Frequently Asked Questions about Chart Rendering API

What is the /render/transit-gantt endpoint?

What is the /render/graphic-ephemeris endpoint?

What is Ebertin Cosmobiology?

Why is the 4th harmonic 22.5° the standard?

Are SVG layers named for downstream styling?

What chart themes are available?

Can I get an Astrocom-style chart?

How do I customize axis thickness?

Can I hide specific planets from aspect lines?

Does the API render Part of Fortune?

Do you support Uranian / Hamburg School planets?

Can I render synastry, transit, and composite charts?

Why did you vendor Kerykeion v4.26.3 instead of just importing it?

Where do house numbers go with house_numbers_position='center'?

What does hide_axes_visually do?

How fast does rendering take?

Which output formats do I get?

Can I override theme settings per request?