BJGE v0.1.0
Astravya Jyotish Research & Calculations
An open record of how our charts are calculated, which classical sources are being researched, and what has actually been tested.
BJGE-MODERN-INDEPENDENT-v1
Modern astronomy profile — in use
Planet positions from modern numerical astronomy (VSOP87D, ELP2000-82B) through an MIT-licensed library, converted to the sidereal zodiac with the Lahiri ayanamsa. No Swiss Ephemeris code or data.
No published test run yet.
BJGE-SURYA-CLASSICAL-v1
Classical Surya Siddhanta profile — pending
Will follow the documented procedures of a specific edition. Its results represent a historical model and are expected to differ from modern positions. It is not used for any customer chart until its sources, constants and tests are verified.
Formula register
| Formula | Method | Source | Status |
|---|---|---|---|
| F-TIME-001 Local civil time → UTC | UTC = local − offset(zone, instant), offset from the IANA time-zone database (historical rules included) | Modern civil timekeeping (IANA tz database). Not a classical rule. | UNVERIFIED — REVIEW PENDING |
| F-TIME-002 Julian Day (UT) | JD = Unix_ms / 86 400 000 + 2 440 587.5 | Standard astronomical day count (Scaliger/Herschel convention). Modern, not classical. | UNVERIFIED — REVIEW PENDING |
| F-TIME-003 Ahargana (civil days since Kali epoch) | Ahargana = floor(JD + 0.5) − floor(JD_kali + 0.5), JD_kali = 588 465.5 (provisional) | Kali-yuga epoch as commonly cited for Surya Siddhanta. Chapter/verse and Ujjain-midnight convention PENDING verification in SS-BURGESS-1860. | UNVERIFIED — REVIEW PENDING |
| F-MOD-001 Apparent geocentric tropical longitude | λ_trop = ecliptic-of-date longitude of apparent geocentric vector (VSOP87D planets, ELP2000-82B Moon, IAU2000B nutation, light-time & aberration) | Modern numerical astronomy via an MIT-licensed library. Not a classical formula. | UNVERIFIED — REVIEW PENDING |
| F-MOD-002 Mean lunar node (Rahu) | Ω = 125.0445479 − 1934.1362891·T + 0.0020754·T² + T³/467 441 − T⁴/60 616 000, T = (JD − 2451545)/36525 | Meeus-style polynomial (Chapront et al.). Modern. | UNVERIFIED — REVIEW PENDING |
| F-MOD-003 Lahiri (Chitrapaksha) ayanamsa | ayanamsa = λ_trop(Spica, apparent) − 180° | True-Chitrapaksha definition (Spica fixed at 0° Libra sidereal). Convention, not a classical verse. | UNVERIFIED — REVIEW PENDING |
| F-MOD-004 Tropical ascendant (Lagna) | λ_asc = atan2(cos θ, −(sin θ cos ε + tan φ sin ε)), θ = local sidereal time | Standard spherical-astronomy ascendant. Modern; checked against NASA Horizons local sidereal time. | UNVERIFIED — REVIEW PENDING |
| F-SID-001 Sidereal longitude | λ_sid = Normalize360(λ_trop − ayanamsa) | Definition of a sidereal zodiac offset. | UNVERIFIED — REVIEW PENDING |
| F-SID-002 Rashi | rashi_index = floor(λ_sid / 30°); degree_in_rashi = λ_sid mod 30° | Twelve equal 30° rashis. Classical passage to be linked after verification. | UNVERIFIED — REVIEW PENDING |
| F-SID-003 Nakshatra | nakshatra_index = floor(λ_sid / (360°/27)) | 27 equal nakshatras. Classical passage to be linked after verification. | UNVERIFIED — REVIEW PENDING |
| F-SID-004 Nakshatra pada | pada = floor((λ_sid mod 13°20′) / 3°20′) + 1 | Four equal padas per nakshatra. Classical passage to be linked after verification. | UNVERIFIED — REVIEW PENDING |
| F-SS-001 Surya Siddhanta mean motion (madhyama) | mean = 360° × frac(rev_Age × ahargana / 1,577,917,828); slow apsides/nodes: 360° × frac(rev_Aeon × Y / 4,320,000,000), Y = years since creation | SS-BURGESS-1860 I.29–34, I.37, I.41–48, I.57–58. DRAFT developer transcription from the archive.org OCR (jstor-592174); reviewer check of printed page pending. | UNVERIFIED — REVIEW PENDING |
| F-SS-002 Surya Siddhanta manda correction | kendra = apsis − planet; P = P_even + (P_odd − P_even)·bhujajya/R; eq = arcjya(bhujajya·P/360), + if kendra in Aries half, − in Libra half | SS-BURGESS-1860 II.29–31, II.34–35, II.38–39, II.43, II.45. DRAFT transcription. | UNVERIFIED — REVIEW PENDING |
| F-SS-003 Surya Siddhanta sighra correction | kendra = sighra − planet; K = √((R ± kotiphala)² + bhujaphala²); eq = arcjya(bhujaphala·R/K); four steps: ½ sighra, ½ manda, whole manda on mean, whole sighra | SS-BURGESS-1860 II.36–37, II.40–45. Step order follows Burgess's reading of II.44 — interpretation pending mathematical review. | UNVERIFIED — REVIEW PENDING |
| F-SS-004 Surya Siddhanta precession (ayana) | revs = 600·ahargana / civil days in an Age; ayana = bhuja-arc(revs fraction × 360°) × 3/10 | SS-BURGESS-1860 III.9–12. Direction of application (III.11–12) is an interpretation pending mathematical review. | UNVERIFIED — REVIEW PENDING |
| F-SS-005 Surya Siddhanta lagna (rising point) | sin δ = sin λ·1397/R; day-radius = R − vers δ; earth-sine = sin δ·palabha/12; sin cara = earth-sine·R/day-radius; sign risings = Lanka times ∓ carakhanda; lagna by subtracting sign risings from asu since sunrise | SS-BURGESS-1860 II.28, II.60–62, III.17, III.42–48. Local mean time, noon at 12:00 LMT and 900 asu per hour are MODERN assumptions. | UNVERIFIED — REVIEW PENDING |
| F-NAK-001 Surya Siddhanta nakshatra of the Moon | nakshatra = floor(λ_Moon′ / 800′) + 1; elapsed = λ_Moon′ mod 800′; start/end = roots of λ_Moon = 800′·k in the classical model | SS-BURGESS-1860 II.64; Moon from F-SS-001..003 (I.29–34, II.29–45). DRAFT transcription. Names are the conventional list; padas are not in the text and are not computed; start/end by root search (modern computational choice). | UNVERIFIED — REVIEW PENDING |
| F-PAN-001 Tithi and karana | tithi = floor((λ_Moon − λ_Sun)′ / 720′) + 1; karana = floor((λ_Moon − λ_Sun)′ / 360′) + 1; end instant = root of (λ_Moon − λ_Sun) = 12°·tithi in the profile's own model | SS-BURGESS-1860 II.64, II.66–69. DRAFT transcription from the archive.org OCR. End time found by root search instead of II.66's linear daily-motion rule (a modern computational choice). Movable karana names are the conventional list, not quoted from the edition. | UNVERIFIED — REVIEW PENDING |
| F-PAN-002 Nakshatra, yoga and vara | nakshatra = floor(λ_Moon′ / 800′) + 1; yoga = floor((λ_Sun + λ_Moon)′ / 800′) + 1; vara = (floor(JD + 1.5) mod 7), 0 = Sunday | SS-BURGESS-1860 II.64–65; I.66 (week-day begins at midnight, corrected for desantara — desantara not yet applied; the civil date is used). DRAFT. Modern profile uses Lahiri sidereal longitudes. | UNVERIFIED — REVIEW PENDING |
| F-DAS-001 Vimshottari starting lord and balance at birth | n = floor(λ_Moon′ / 800′); lord = ORDER[n mod 9]; balance = years(lord) × (800′ − (λ_Moon′ mod 800′)) / 800′ | Vimshottari is a Parashari dasha system, not a Surya Siddhanta rule. Classical source (Brihat Parashara Hora Shastra) not yet in the research library — no chapter/verse recorded. Moon from F-MOD-001 and F-MOD-003. | UNVERIFIED — REVIEW PENDING |
| F-DAS-002 Vimshottari mahadasha sequence and lengths | start₀ = birth − (years(lord₀) − balance); startₖ₊₁ = startₖ + years(ORDER[(n+k) mod 9]) | Period lengths are the conventional Vimshottari values; classical citation not yet located in a library edition. | UNVERIFIED — REVIEW PENDING |
| F-DAS-003 Vimshottari antardasha division | antar(M, A) = years(M) × years(A) / 120, in order starting with M | Proportional subdivision is the conventional rule; classical citation not yet located in a library edition. | UNVERIFIED — REVIEW PENDING |
| F-DAS-004 Dasha year length | 1 dasha year = 365.2425 days (Gregorian mean year) | Modern computational convention used by the customer engine. Traditions differ (e.g. 360-day or sidereal years); a reviewer must choose and record the convention. | UNVERIFIED — REVIEW PENDING |
Classical source research is carried out privately by Astravya's research team. A formula or passage is shown as approved here only after named reviewers have signed it off.
Verified passages
No passages have completed verification yet. We do not publish unverified verses.
Astronomical positions are calculations; interpretations are traditional and not scientific predictions. See also calculation methodology.