Calculated positions.
Honest interpretation.
Kendraya Engine calculates every chart from NASA/JPL DE440s, the planetary ephemeris of NASA’s Jet Propulsion Laboratory. Kendraya turns your birth time and place into apparent positions seen from the Earth, then applies astrology’s zodiac, house and period conventions.
Planetary positions are supported from 1900 to 2100, and births from 1900 to today. This page sets out each step and setting so an astrologer can compare a Kendraya chart with any other, and so anyone can see where calculation ends and interpretation begins.
- Engine
- Kendraya Engine
kendraya-jpl-2 - Orbital data
- NASA/JPL DE440s
- Planet positions
- 1900 to 2100
- Largest audit difference
- 0.757 arcseconds
Last updated 3 October 2026
What happens between your birth details and your chart?
Four steps, in a fixed order. The first three are astronomy and timekeeping, and they would be the same for any tradition. The fourth applies astrological conventions, which is why two careful astrologers can disagree about a sign while agreeing about the sky.
1. Your clock and place
The local time on your birth record and your birthplace become one exact instant, using that place’s historical time-zone and daylight-saving rules.
2. JPL orbital data
Kendraya’s own file reader interpolates the NASA/JPL DE440s ephemeris to find where the Sun, Moon, planets and Earth were at that instant.
3. The sky seen from Earth
Light travel time, the Sun’s bending of light and the Earth’s own motion are applied, giving apparent geocentric positions on the ecliptic of that date.
4. Zodiac, houses and tradition
Only now are astrological conventions applied: a tropical or sidereal zodiac, houses from your rising sign, nakshatras and life periods.
Why Kendraya asks for three details
- Birth date places you in the planetary cycles.
- Birth time is the local clock time on your birth record. It fixes the Moon’s degree, your rising sign and the houses.
- Birthplace gives the horizon and the historical time zone. A town or city supplies reference coordinates; you can enter the birth coordinates for a more specific location.
Your local time is converted to Universal Time using the historical time-zone records for the place you name, including the daylight-saving rules in force at the time. If your birth clock time never existed (the clocks jumped forward) Kendraya says so rather than guessing. If it happened twice (the clocks went back) you choose which occurrence applies.
What if I don’t know my birth time?
Tick “I don’t know my birth time” and Kendraya uses local noon on your birth date as a reference. Your Sun and the slower planets are reliable at that resolution. The Moon moves about 13 degrees a day, so any placement that changes sign during your birth day is marked as uncertain. Because they depend on the exact minute, the rising sign, houses, Moon mansion and Vimshottari periods are withheld rather than approximated.
Where do the planetary positions come from?
An ephemeris is a table, or a mathematical model, of where solar system bodies are over time. JPL’s DE440 model was fitted to decades of observations of the planets, the Moon and spacecraft, and is described in Park and colleagues (2021). DE440s is JPL’s compact edition of it, covering 1849 to 2150. JPL supplies the astronomy only. It has no zodiac, houses or interpretation, and it does not endorse Kendraya.
Kendraya bundles the unmodified de440s.bsp file, as published by NASA/JPL NAIF, on Kendraya’s server. It never runs in your browser, and no outside data service is called when a chart is calculated. Before first use the engine checks the file’s SHA-256 fingerprint and coverage. If either check fails, the calculation stops with an error instead of falling back to a different engine.
The file stores each body’s path as Chebyshev polynomial coefficients. Kendraya reads them with its own reader, written from NAIF’s published format specification, and evaluates them for your instant. This is interpolation of JPL’s solution, not a new orbital theory. The engine then works out what an observer at the Earth’s centre would see: it allows for the time light takes to arrive, the slight bending of light by the Sun’s gravity, and the aberration caused by the Earth’s orbital motion, then expresses the result on the ecliptic and equinox of that date. JPL also publishes newer ephemerides, including DE442. Kendraya does not switch automatically; any change of dataset would be a new, separately audited engine version.
How is a birth clock time turned into an exact instant?
Clocks follow the Earth’s rotation, which is slightly irregular, while orbital models run on a uniform time scale. Kendraya keeps these apart: civil time (UTC), Earth-rotation time (UT1), Terrestrial Time (TT) and the barycentric time used by the ephemeris (TDB) are separate steps. The difference between them comes from measured records stored with the engine: IERS Earth-orientation series from 1962, US Naval Observatory history for earlier years, and the IERS table of announced leap seconds.
Before 1960, civil Universal Time is treated as UT1. Beyond the published records, Earth rotation follows a labelled model and future UTC assumes no unannounced leap seconds, so a future clock time is an estimate, not an observation. Results close to a sign or house boundary can shift when newer records arrive.
How closely do Kendraya’s positions match NASA/JPL Horizons?
Kendraya Engine was compared with JPL’s Horizons service at 256 fixed instants spread from 1 January 1900 to 31 December 2100, for 10 bodies: 2,560 pairs of apparent geocentric ecliptic longitude and latitude. Every pair passed the 5-arcsecond limit per axis. The largest longitude difference was 0.284″ (Uranus) and the largest latitude difference 0.757″ (Venus).
An arcsecond is 1/3600 of a degree. For a real chart, an accurately recorded birth time and matching conventions (zodiac, ayanamsa, houses and nodes) matter as much as the ephemeris.
| Body | Kendraya target | Longitude | Latitude |
|---|---|---|---|
| Sun | Body centre | 0.121 | 0.001 |
| Moon | Body centre | 0.120 | 0.001 |
| Mercury | Body centre | 0.121 | 0.001 |
| Venus | Body centre | 0.219 | 0.757 |
| Mars | System barycentre | 0.121 | 0.001 |
| Jupiter | System barycentre | 0.169 | 0.004 |
| Saturn | System barycentre | 0.163 | 0.024 |
| Uranus | System barycentre | 0.284 | 0.010 |
| Neptune | System barycentre | 0.217 | 0.006 |
| Pluto | System barycentre | 0.192 | 0.094 |
What this comparison does not show
- It is agreement at sampled instants, not a guarantee of the same agreement at every moment.
- Horizons and DE440s come from the same JPL ephemeris family. The archived Horizons responses used DE441 and body-specific JPL satellite solutions, so the differences include those ephemeris and target-point choices as well as Kendraya’s calculation. This checks computed output; it is not a bound on accuracy against real observations.
- The instants are given directly in Terrestrial Time. The comparison does not test how a recorded birth clock time becomes UTC and UT1, and it does not check houses, nodes, ayanamsa values, dasha dates or any traditional meaning.
- Mars through Pluto are calculated at the centre of mass of each planet and its moons. Horizons reports the planet itself, and those differences are included in the figures above.
Audit run 3 October 2026 (America/New_York) on engine kendraya-jpl-2, against Horizons responses captured 30 September 2026. Download the audit summary (JSON) with the sample counts, reference settings, data fingerprints and limitations.
Vedic and Western views
The Vedic view uses the sidereal zodiac with the Lahiri ayanamsa, the convention most Indian and Sri Lankan astrologers use. The Western view uses the tropical zodiac, anchored to the March equinox. Both are exact coordinate systems. They currently differ by about 24 degrees, so a planet may appear in a different sign in each. Nakshatras and Vimshottari periods belong to the sidereal tradition, so they are shown in the Vedic reading. D9 and D10 always use the selected sidereal convention, including when explored from the Western view. The birth wheel shows the classical planets and lunar nodes. Personal timelines also calculate outer-planet transits. Whole-sign houses are the default; equal houses are available in Chart & details.
The calculation settings
Every setting that changes a sign, house or date is listed here. Each chart’s receipt records the ones it used.
| Setting | Kendraya uses |
|---|---|
| Orbital data | NASA/JPL DE440s (unmodified file, SHA-256 fingerprint checked), read by Kendraya’s own SPK reader. Dataset version de440s-iers-2026-09-30 |
| Positions | Apparent geocentric ecliptic longitude and latitude of date, with light time, solar light deflection (not for the Sun itself) and relativistic annual aberration |
| Reference frame | IAU 1976 precession and IAU 1980 nutation |
| Body centres | Sun, Moon, Mercury and Venus at their centres; Mars, Jupiter, Saturn, Uranus, Neptune and Pluto at their system barycentres (planet plus moons) |
| Observer | The Earth’s centre for every birth position. Your birthplace sets the clock conversion, horizon and ascendant. Rise, set and lunar calendar tools observe from the birthplace separately. |
| Time scales | UTC, UT1, TT and TDB kept distinct, using IERS and US Naval Observatory records; modelled beyond them, with no unannounced leap seconds |
| Bodies in the birth chart | Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Rahu and Ketu. Uranus, Neptune and Pluto appear in personal timelines and the API. |
| Lunar nodes | Mean node (IERS 2003 expression) by default. Option: true node, the instantaneous node of the Moon’s osculating orbit from its geometric position and velocity. Ketu is always opposite Rahu. |
| Zodiac | Tropical, or sidereal with the revised IAE Lahiri ayanamsa: 23°15′00.658″ at 21 March 1956 (TT), carried to other dates with IAU 1976 precession. A documented fixed offset is also available; it is not an evolving historical ayanamsa model. |
| Houses | Whole sign, counted from the rising sign (default), or equal 30° houses counted from the rising degree |
| Nakshatra | 27 equal mansions of 13°20′ from 0° sidereal Aries, four padas each |
| Vimshottari dasha | Ketu 7, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, Mercury 17 years; balance at birth from the Moon’s arc through its nakshatra; default year of 365.25636 days. Options: 365.2422 or 360 days. |
| Daily transits | Conjunction, sextile, square, trine and opposition within a 3° orb, compared with your natal positions |
| Date range | Births from 1900 to today; planetary calculations through 2100 |
Other software may use a different ayanamsa, house system, node or dasha year, and will then show different signs, houses or period dates. None of these is “more correct”; they are conventions, and Kendraya states its own so you can compare. A paper chart from 1980 can be compared meaningfully when its birth details, ayanamsa, node and period conventions are known. Identical output cannot be promised from the year alone, and a difference alone does not show that either chart is wrong.
Advanced tools and their limits
These tools use the same positions. Open any of them for the detail behind it.
Birth-time sensitivity and the calculation receipt
Chart & details lets you compare a window around your recorded birth time. The view distinguishes factors that change from factors that stay the same in the sampled moments. Known times are sampled every minute; unknown times across the birth day are sampled every 15 minutes. These samples cannot rule out every brief boundary crossing, and do not determine an unknown birth time.
Each chart has a receipt recording its UTC birth moment, zodiac, houses, nodes, year convention, time-zone source, engine version and data fingerprints. A documented manual UTC offset can be used for a historical birth record. It changes the birth clock conversion only. The receipt contains personal information, so keep it somewhere private.
Love, connection and personal timing
Relationship reflections point to visible natal factors such as Venus, the Moon, Mars, Mercury and the seventh house. Synastry compares major angles between two charts using the same zodiac and astronomical conventions, while keeping each person’s own clock conversion. It offers questions for conversation without assigning a compatibility score or predicting another person’s feelings.
The personal timeline finds exact longitude contacts over 7, 30 or 90 days and the next solar and lunar returns. Its numerical search precision is separate from uncertainty in birth time, future clocks and physical models. These are return moments, not relocated return-house charts. Exact personal timing is withheld when the birth time is unknown.
Divisional charts and the lunar calendar
Navamsa (D9) and Dashamsa (D10) apply documented traditional divisions to sidereal positions. Their coordinates are symbolic subdivisions, not physical locations of additional planets. Birth-time uncertainty can change these charts rapidly. Divisional houses always use whole signs.
The instant Panchanga shows tithi, nakshatra, yoga and karana with their next transition times, plus the local civil weekday at the birth location. It does not assign sunrise-based religious days or festival dates. Lunar phases, sign crossings and retrograde stations are all solved from the calculated positions.
Today’s reading and life-period dates
Inside a chart, today’s reading is calculated for the moment you open or refresh it, and the page shows that moment and its time zone. The days ahead, and the comparison with yesterday, use the same clock time on each date in your device’s time zone, so a day with a clock change still counts as one day. Your birth moment always uses the birthplace’s own time-zone history. The overview’s short explanations name the placement, method and tradition behind each sentence. Its life-period description is the general theme of the ruling planet, not yet a reading of that planet in your own chart.
The first Vimshottari period is already partly elapsed at birth, so its theoretical start date can fall before you were born. That is a feature of the calculation, not a reading of a life before birth. Period dates are symbolic chapters, not predictions of events or lifespan.
Calculated positions have finite precision. An uncertain birth time, approximate coordinates or an incomplete historical time-zone record can affect the result, especially near a sign or house boundary.
What is calculated and what is written
Positions, signs, houses, nakshatras, period dates, Moon phases and transits are calculated. The sign descriptions, planet introductions, nakshatra themes, life chapter reflections and daily questions are Kendraya’s own editorial writing, informed by classical Vedic sources but not quoted from them. They are offered as prompts for reflection, never as predictions, and Kendraya does not reproduce the health, death, fertility, caste or gender judgements found in historical texts. The precision of the astronomy says nothing about whether astrology’s interpretations are true. The landing page shows the actual planetary positions for today; the wheel inside your chart plots your own calculated longitudes.
A reading is an invitation to notice and reflect. It does not decide your identity, your relationships or your future. Kendraya does not provide medical, legal or financial advice and does not tell you whom to marry or what will happen to you. See the terms of use for the full statement.
Private by design
Birth details travel in the body of a secure request, are used in memory to calculate the chart and are not stored on a server. Nothing is placed in a web address or a log. Saving a profile or a journal note keeps it in your own browser only, and only if you choose to. Analytics load only after you allow them and record page views without birth details. The privacy policy has the details.
Sources and notices
The primary sources behind the engine, and what each one supports. The full licence texts and attributions, including the ERFA copyright notice, are in the calculation notices. NASA, JPL, IERS and the ERFA and SOFA authors do not endorse Kendraya.
- The JPL Planetary and Lunar Ephemerides DE440 and DE441. Park, Folkner, Williams and Boggs, The Astronomical Journal 161:105 (2021). How JPL built and fitted the DE440 orbital model. It describes the astronomy only, not any astrological rule.
- Planetary and lunar ephemerides DE440 and DE441. NASA/JPL Solar System Dynamics. JPL’s own description of the ephemeris family and its intended use.
- Generic planetary SPK kernels. NASA/JPL Navigation and Ancillary Information Facility (NAIF). Where the unmodified de440s.bsp file comes from. Newer ephemerides, including DE442, are published there too; Kendraya does not switch automatically.
- Rules for using NAIF data. NASA/JPL NAIF. Permission to use and redistribute unmodified kernels. It implies no endorsement.
- Horizons System manual. NASA/JPL Solar System Dynamics. Defines the reference positions used in the accuracy audit.
- IERS EOP 20u24 C04 Earth orientation series. International Earth Rotation and Reference Systems Service (IERS). Measured Earth rotation (UT1 minus UTC) from 1962.
- IERS Bulletin A, finals2000A. IERS Rapid Service/Prediction Centre at USNO. Recent and predicted Earth rotation.
- Historic delta T. United States Naval Observatory. Earth-rotation history before 1962.
- IERS Bulletin C leap-second table. IERS. Announced leap seconds. Future ones are never assumed.
- Polynomial expressions for delta T. Espenak and Meeus, NASA Goddard Space Flight Center. The labelled model for Earth rotation beyond the published records.
- ERFA, Essential Routines for Fundamental Astronomy. Liberfa, derived from IAU SOFA. Precession, nutation, aberration, light-deflection and TDB formulas, adapted under its BSD licence.
- Standards of Fundamental Astronomy. International Astronomical Union SOFA Board. The IAU reference library from which ERFA is derived. Kendraya is not SOFA.
- Kendraya Engine position audit against NASA/JPL Horizons. Kendraya, 3 October 2026. The sampled comparison summarised above.