Product blueprint · from the research paper

How astro.desireddy.com becomes an observatory, a library and a conscience: twelve features, the engine and its accuracy budget, the sourcing architecture, the guardrails, the business model and the roadmap. The evidence behind each line is in the research paper.

#The blueprint

#Twelve features no competitor combines

The market splits into Indian reference sites that earn from search traffic, Indian consultation marketplaces, and Western design-led apps. Drik Panchang draws about 11.7–11.9 million visits a month on programmatic city-by-date panchang pages (Semrush). AstroTalk reported about ₹1,176 crore in FY25 revenue. About 65% of its consultation revenue comes from marriage questions, and its remedy store took in more than ₹140 crore in its first year (Inc42). Midjourney bought Co-Star in July 2026 (Bloomberg Law). The complaints users make are consistent: gemstone pressure, fear-then-pay selling, contradictory astrologers, and AI-written reports full of errors (Outlook Money; r/vedicastrologyexperts mirror). CHANI's case that AI blends schools and misstates placements, and its choice to stay human-authored, shows that authenticity is the scarce good (CHANI). The features below target that gap. The uniqueness claims come from this session's review, not from a full competitor audit, which is a task for Phase 0.

#The engine: a JPL-grade core, stated conventions and published tests

Ephemeris. Use the Swiss Ephemeris as the core. It reproduces JPL to 0.001″, has been based on DE441 since May 2026, and ships every Indian ayanamsa and house system (Swiss Ephemeris info). Compile it to WebAssembly. Bundle only the 1800–2400 files, about 0.5 MB for planets plus 1.3 MB for the Moon, which fit on Cloudflare Workers (swisseph/ephe). Dates outside that range use the file-free Moshier mode, accurate to under an arcsecond for planets. The full 97 MB file set can live in R2 storage if it is ever needed.

Licence. Licensing is the first decision to make. Swiss Ephemeris is dual-licensed under the AGPL or a Professional License, and the choice must be made before any public service goes live (LICENSE). The current price page lists an unlimited professional licence at CHF 700. Older documentation gives CHF 750 or 1,550, so confirm with Astrodienst (price page; docs). Buying the licence keeps the product's code private while the methodology and test vectors are still published openly. The MIT-licensed astronomy-engine (±1′, about 116 KB) is a fallback. Its arcminute accuracy means about 2 minutes of error in tithi end times, which is too coarse for to-the-minute claims (cosinekitty/astronomy).

Ayanamsa and house systems. Default to IAE-style Lahiri: 23°15′00.658″ at 21 March 1956, 0h TT, computed as a true ayanamsa, matching the Rashtriya Panchang lineage. Offer True Chitra, KP, Raman and Fagan-Bradley as options (Swiss Ephemeris docs). Whole-sign houses are the default, with Sripati for bhava-chalita and Placidus for KP.

Time and place. Time is a problem specific to India. Before 1906 the IANA zone Asia/Kolkata applies Madras time (+5:21:10). It also includes the wartime +6:30 offsets of 1941–45. Bombay and Calcutta, however, kept their own local times after 1906, and the tz database does not cover that (IANA tz asia). The engine therefore needs explicit overrides for local mean time and named historical zones. For places, use GeoNames cities500 (CC BY 4.0) with alternate names in Indian scripts (GeoNames).

Numerics. Store each instant as a two-part Julian date. Use Stephenson–Morrison–Hohenkerk ΔT (the difference between atomic and Earth-rotation time). Find every boundary (tithi, nakshatra, sankranti, sunrise, lagna) by bracketed Newton iteration with a bisection fallback, using the planet's analytic speed: the tatkalika gati step.

Rule engine. Every yoga, dasha and varga rule is a predicate carrying a source and variant tag. Strength gating follows BJ XVII.13 and XX.11.

Siddhantic mode. This uses exact rationals, with Burgess's worked examples as golden test vectors.

The accuracy budget shows where errors actually come from. Modern ephemeris error sits about 10,000 times below what minute-level panchang accuracy needs. What decides whether a panchang is right is its conventions, not its mathematics.

Sources for the table: accuracy analysis built on Swiss Ephemeris and NASA ΔT data; Swiss Ephemeris docs.

Validation runs in layers, and every release publishes the results:

1. About 10,000 random instants from 1800 to 2100 against JPL Horizons.
2. Lahiri ayanamsa for each year from 1956 to 2030 against the Indian Astronomical Ephemeris, following Swiss Ephemeris Appendix E.
3. About 200 documented charts, especially pre-1947 Indian births, against Jagannatha Hora with matched settings.
4. A full year of tithi end times at Ujjain, Delhi and Chennai.
5. Textual invariants as unit tests: the 337-point Ashtakavarga and the 31/31/180 lunar-yoga counts.

These tests are themselves marketing. An "open methodology" page that shows the engine version, the conventions and the pass rates is exactly what no competitor offers.

#Content architecture: every sentence traces to a verse, an edition and a licence

The content system has four linked layers.

1. Source registry. It records each edition: its archive.org identifier, translator, year, Indian status, US status, OCR quality and proofreading state. Sources are graded green, amber or red as in the table above. No CC0 tag from an uploader is ever trusted.

2. Passage store. It holds proofread verses. Only green editions may be quoted at length. Amber and red editions may only be paraphrased, cited by chapter and verse, with quotations under 15 words.

3. Rule cards. Each card links a machine predicate to its passages. It carries a school or variant tag and one of three content labels: classical prediction (deterministic in source), classical religious practice, or modern addition. Gemstones fall under the last label, because BPHS does not prescribe them. Cards also carry a sensitivity flag for death, caste, gender-norm and "thief" material.

4. Output layer. It assembles readings only from rule cards whose strength gates pass. Each sentence carries its card ID.

On top of this sit history pages using the "Documented / Attributed / Legendary" chip scheme, sage pages arranged as "What tradition says / What texts bear his name / What scholars date them to / Where to read it free", and verified-only quotation cards.

Two content investments matter most. First, commission a new English translation of BPHS from the 1905 Venkateswara Sanskrit text, with Hindi, Telugu and Tamil versions after it. This fills the biggest public-domain gap on the internet and becomes an asset the site owns. Second, run a proofreading pipeline for the green core: Aiyar's Brihat Jataka, Iyer's Brihat Samhita, Rao's 1899 and 1900 translations, Kalaprakasika, Burgess, Clark, Shamasastry and Pope. Search the Jangamwadi collection in roman script for its regional commentaries. The same rule cards can also generate search-friendly reference pages: nakshatra pages, planet-in-sign and planet-in-house pages, yoga dictionary entries with the computable rule, and city-by-date panchang and festival pages in four languages. Each one carries citations that competing pages lack.

#Ethics and regulatory guardrails written into code

The guardrails are product rules, not disclaimers.

Fear-based predictions are off by default. The engine computes balarishta, maraka, Shula Dasha, Kalachakra death effects, longevity and widowhood, but never displays them to end users. Classical text on these topics appears only in clearly framed historical study pages. Sensitive classical material, such as caste attributions and the female-horoscopy chapters, is suppressed by default. These rules follow from Sharma's non-harm argument, from Brihat Samhita 2's requirement that the astrologer be free of malice, and from the documented fear-then-pay scam pattern.

Nothing is sold as a remedy. The site sells no gemstones, pujas or yantras and runs no remedy affiliate links. Remedies, where shown, are limited to free behavioural, charitable or devotional practices in the Lal Kitab style. They are labelled "traditional, untested" and framed through the Jain critique of nidana, never as transactions.

The law reinforces this. India's Drugs and Magic Remedies Act 1954 bars advertising talismans or mantras as cures for scheduled diseases, conception or sexual function, with prison terms for violations (iPleaders). Two CCPA instruments apply as well: the Misleading Advertisements guidelines of 9 June 2022, and the Dark Patterns guidelines of 30 November 2023, which ban false urgency and fake scarcity among 13 listed patterns (Mondaq; JSA). The site therefore has no countdown banners and no flows that move from fear to purchase. Abroad, the UK BCAP code permits horoscope advertising only as entertainment, and France's ARPP code bans promises of guaranteed results (ASA/BCAP; ARPP).

Birth data is treated as personal data. The DPDP Rules were notified in November 2025. Consent-manager provisions apply from November 2026, and notice, consent, security and breach duties from about May 2027, with penalties up to ₹250 crore (DSK Legal). The site therefore asks for no contacts and requires no social login. Charts are stored local-first or encrypted, deletion takes one click, and birth data is never used for training.

AI only explains what the engine computed. The LLM never computes positions. In a vendor test, a frontier model put the ascendant in the wrong sign (RoxyAPI). Every AI sentence must cite a rule-card ID, uncited sentences are blocked, and all AI text is labelled.

The evidence is stated plainly. An "Evidence" page reports Carlson's 1985 double-blind test, in which subjects picked their own chart in 28 of 83 cases, about chance for a three-way choice. It also reports Ertel's reanalysis at p = .054 and Dean & Kelly's meta-analysis of more than 40 studies, with time twins showing no predicted similarity (IMSc summary; Dean & Kelly 2003). Positioning Jyotisha as a living textual tradition and a reflective practice, not as deterministic prediction, is both more honest and legally safer. Web-first delivery also avoids Apple's guideline 4.3, under which astrology apps are rejected unless they are "unique, high-quality" (Apple Developer Forums).

#A business model that earns without selling fear

The revenue lines are the ones the market notes call ethical. Each also strengthens the moat instead of eroding it:

• Free tier: charts, the panchang and the heritage library, with citations. This wins search traffic the way Drik Panchang and Prokerala do.
• Subscription: the deep tools, including school comparison, Varshaphal, explainable muhurta, prashna journaling and exportable reports.
• Paid courses: taught from the proofread public-domain corpus and the commissioned BPHS translation, with a certificate that tests both calculation and ethics.
• Optional consultations: with vetted astrologers at transparent flat fees, not per-minute billing that rewards keeping users on the line. Paid endorsements are disclosed under the 2022 guidelines.
• B2B API: for the cited rule engine and the validated panchang.

The site will not sell gemstones, pujas or "parihara" packages. AstroTalk shows those can earn hundreds of crores, but they are the main source of the trust deficit this site exists to fix. The diaspora is a large adjacent audience: about 37% of AstroTalk's FY26 revenue was international, with the US over 60% of that (Inc42). That argues for English-first design with Indic-language parity, priced in USD and INR.

#A phased roadmap to launch before India's privacy duties take effect

Windows are recommendations keyed to today's date (14 October 2026) and to the DPDP phase-in. They are not sourced estimates of effort.