CHAKRA — Temporal Cycle Observatory

One offline HTML file family that is simultaneously: a geared solar-system observatory, a 12-tradition calendrical almanac with a computed festival engine, a jyotiṣa instrument, a telescope-pointing readout, a tested computation library, and a zero-server JSON API.

No dependencies. No network. No tracking. Open index.html from disk and everything runs.

The site

page	what it is
index.html	landing — the Moon as it is right now inside an astrolabe of true planet positions; today across ten calendars; what's coming up
pro.html	the full observatory — nine instruments, every graph an input, ✦ AI prompts per view
learn.html	the mathematics, the schools, the history, the spacecraft — six interactive sims
tour.html	relativistic interstellar tour planner; arrival dates in ten calendars
tests.html	fetches test-plan.json and runs 26 anchored cases in your browser

Themes: append ?theme=solar (or terminal, contrast) to any page.

Quick start

git clone https://github.com/project-ilm/chakra && cd chakra
xdg-open index.html          # or just double-click it
node test/run.js             # 9 suites · 98 assertions · exits non-zero on failure

The URL is an API

Append ?api=… and the same file answers in JSON instead of pixels:

index.html?api=panchang&date=2026-08-12&lat=28.61&lon=77.21&tz=5.5
index.html?api=telescope&date=2026-07-04&time=21:30&lat=17.38&lon=78.48&tz=5.5
index.html?api=calendars&date=2026-06-16        ← the day Sunni and Shia tabular Hijrī diverge
index.html?api=yogas | dasha | chart | eclipses | almanac | moment | events&year=2026

Headless too: require("./src/chakra-kernel.js").create({...}).moment() in Node.

What's inside

• Observatory — draggable geared orrery; drag any graph to set the epoch; drag the ascendant hand and CHAKRA solves for the time; click a spectrum peak to phase-lock; click an eclipse or festival to travel there. Every graph is an input.
• Calendars, side by side — Gregorian/JD · tabular Hijrī · Sunni & Shia tabular reckonings separately · Solar Hijrī · Vedic (saṁvatsara/Śaka/Vikrama/Kali) · Hebrew · Sikh Nanakshahi · Chinese sexagenary · Tibetan · Mayan Long Count · precessional age.
• Computed festivals — annualEvents(Y): amānta Hindu months by the classical saṅkrānti rule (adhika-māsa handled), Islamic dates in both reckonings, Jewish, Sikh, all saṅkrāntis, the year's eclipses. 2026 verified: Holi lands on the 3 March lunar eclipse, Dīpāvalī 9 Nov (tithi-instant convention — docs/ASSUMPTIONS.md), Mahāśivarātri 15 Feb — 15/15 test assertions.
• Jyotiṣa — pañcāṅga (tithi/nakṣatra/yoga/karaṇa + Sufi manzil), rāśi chart, Kālasarpa · Maṅgala Doṣa · Gaja-Kesari · Mahāpuruṣa · Sāḍe-Sātī and more, Vimśottarī mahādaśā timeline. Framed as cultural computation, never prediction.
• Sky & telescope — dome/AR sky with all 27 nakṣatra yogatārās; RA/Dec · Alt/Az · hour-angle for the nine grahas, on screen and over the API.
• Printable almanac — 🖨 button; @media print produces a clean festival sheet.

Architecture (see docs/ARCHITECTURE.md)

index.html  →  chakra-ui.js  /  chakra-api.js
                     ↓              ↓
               chakra-kernel.js (state · moment() · bus · inverse solvers)
                     ↓
               chakra-core.js  (pure: ephemeris · calendars · yoga · events)

The core is UMD — the identical file runs in the browser and under require() in Node, which is how the test suite consumes it.

Verification anchors (all in test/)

Spica sidereal 179.99° (the Lahiri definition) · all four 2026 eclipses on exact dates (17 Feb, 3 Mar, 12 Aug, 28 Aug) · full moon 2026-06-29 at elongation 180.000° · ascendant solver residual 0.0000° · Hebrew epoch calibrated to four published dates · Sunni/Shia divergence 2026-06-16 · 15 festival anchors for 2026.

Precision, honestly

Low-precision analytic ephemeris (arcminutes for Sun/Moon, ≲1° planets), no ΔT/refraction/parallax, tabular (not sighted) Hijrī, noon-tithi convention (±1 day vs sunrise-rule panchāṅgas). Full detail: docs/ASSUMPTIONS.md. Feature matrix vs Drik Panchang / Jagannatha Hora / Stellarium / SkySafari — including where CHAKRA loses: docs/COMPARISON.md.

The core in C (lib/)

The same engine in C99 for firmware, kiosks and e-paper: make && make test builds libchakra.a, a JSON CLI, and runs a 6,590-check parity harness against vectors generated from the JS reference — calendar fields exact, festival strings byte-identical (diacritics included). No heap, -lm only. See lib/README.md.

License & authorship

Code GPL-3.0-or-later (LICENSE) · documentation CC BY-SA 4.0 (LICENSE-docs) · © 1993–2026 Abhishek Choudhary, sole author. Not for navigation, muhūrta-critical, or safety-critical use — DISCLAIMER.md.

Part of Project ILM · https://github.com/project-ilm · live: https://project-ilm.github.io/chakra/