What is calculated, what is traditional, and what is interpretation

Astronomical position

Sun and Moon tropical ecliptic longitudes are calculated with the open-source Astronomy Engine library. Vedic Sky then converts those longitudes to a sidereal frame for the Vedic calculations. Location and civil time are also used for place-dependent quantities such as sunrise, sunset and the ascendant.

Lahiri sidereal conversion

The current engine uses an isolated Lahiri (Chitrapaksha) ayanamsha approximation. It is anchored to 23.85709° at J2000 and advances precession using an IAU-2006 general-precession polynomial. The implementation was designed against Swiss Ephemeris / Indian Astronomical Ephemeris behaviour as a validation target, but Vedic Sky is not itself running Swiss Ephemeris.

This matters near sign, Nakshatra or Yoga boundaries: small implementation differences can move a transition by a short amount of time. The ayanamsha function is deliberately isolated so it can be replaced by a more rigorously validated implementation without rewriting downstream logic.

Deterministic Vedic divisions

The sidereal Moon is divided into 27 equal Nakshatras of 13°20′, each divided into four padas. Nitya Yoga is calculated from the normalised sum of the sidereal Sun and Moon longitudes and divided into the same 27 equal spans.

Tithi is derived from Moon–Sun angular separation in 12° segments; Karana from 6° half-Tithi segments; Paksha from the waxing or waning half of the lunation. The Vara day boundary follows local sunrise when a valid sunrise is available, with a civil-day fallback when it is not.

When Vedic Sky has to summarise one civil date with a single instant, it uses local noon. This is a display and navigation convention, not the traditional rule for naming a Panchang day. A printed Panchang may instead identify the day by the Tithi present at sunrise. For a class, appointment or other specific event, use the sky at that actual time rather than treating the noon summary as the event sky.

Personal calculations

My Sky uses the birth date, birth time, birthplace coordinates and time zone you provide to calculate a natal reference. Current-sky measurements are then compared with that natal reference for features such as Tarabala and Chandrabala. These are rule-based calculations, not machine-learning personality inference.

The My Sky headline combines those lunar factors with the same wider Sky reading. The combination is Vedic Sky Clock’s modern reflection. Factors can reinforce or qualify one another; they are not averaged into a score, and personal support does not remove a wider timing caution. Explore the reading to see each factor and how they combine.

Birth-time precision matters. If the recorded time is approximate, fast-changing factors such as the ascendant may also be approximate.

Interpretive language

Descriptions of Nakshatras, Nitya Yogas, planetary symbolism, Tarabala, Chandrabala and related meanings draw on traditional Vedic astrology concepts and editorial synthesis. They are cultural and reflective interpretations, not experimentally established causal effects.

The headline keeps the Nakshatra’s traditional class and adds at most one lunar or timing phrase. The current Nakshatra stays visible. Consecutive Nakshatras can share a class, so a repeated tone can describe a real stretch rather than a new quality each day.

Nakshatra class guidance follows the Bṛhat Saṃhitā. Tithi and paksha supply lunar context. Selected timing considerations follow Muhūrta Cintāmaṇi 1.34–36, using Sharma’s proportional-duration interpretation: an opening portion is measured against the actual duration of that Tithi or Nitya Yoga, rather than a fixed number of clock minutes. Full- and new-Moon context takes headline priority; otherwise an active timing consideration takes priority over the lunar phrase.

These timing considerations concern beginning auspicious work in that tradition. They do not predict mood or constitute a complete choice of an auspicious time. The absence of a listed consideration does not mean a period is favourable. The combined wording is Vedic Sky Clock’s editorial reflection.

Vedic Sky should therefore explain why a reading appears, avoid presenting interpretive language as objective fact, and avoid turning a symbolic system into deterministic instruction.

Three factors, three explanations

Nakshatra describes the Moon’s lunar mansion. Its card explains its symbolic image, deity association and traditional activity class. The small drawings are original Vedic Sky illustrations of symbols used in modern Jyotisha references; traditions can differ. They are not an ancient standardised alphabet. Deity descriptions draw on David Frawley’s account of the Taittiriya Brahmana and its commentary. Symbols and deities explain the mansion’s imagery; the reviewed activity class supplies the headline quality.

Nitya Yoga describes the combined positions of the Sun and Moon. Its card gives a conventional English gloss of the name and the applicable timing consideration. The conventional name meaning is paired with historical activity examples from Veda Samskruti Samiti’s Yoga table. These examples are educational background and do not enter the headline calculation. The emblem is an original Vedic Sky visualisation: one to nine lobes repeat across three groups, counted by one to three inner rings. Its outer marker locates the Yoga among 27. The geometry encodes position, not a traditional glyph, the bodies’ separation or favourability.

Tithi describes the lunar day and its waxing or waning fortnight. Its card explains that place in the lunar cycle, its fivefold classification and any applicable timing consideration. The grouping follows Bṛhat Saṃhitā 99.2 in Iyer’s translation; it does not by itself prescribe an activity. The phase disc uses calculated lunar illumination, shown in a schematic orientation rather than the Moon’s orientation in your local sky.

Name meanings, deity imagery and timing categories describe the tradition, not your emotional state or future. The factors contribute to one reading; none alone establishes an auspicious time. These individual explanations also appear in Today’s Arc. The combined reading and Balance remain in “Explore this reading”. Calculations and source notes can be expanded within each factor card.

Balance and the Yin–Yang motif

Balance is a visual interpretation of receptive/inward and active/outward qualities. It combines editorial qualities assigned to the current Nakshatra, Nitya Yoga, Moon sign, Sun sign and rising sign. The midpoint is relative to a fixed reference catalogue. Tithi and paksha do not contribute to this indicator.

The Yin–Yang motif is a deliberate visual metaphor, not a traditional Panchanga classification. Its position illustrates one of five categories, not a measured percentage. The assignments and their weighting are Vedic Sky Clock conventions; they have not been established as traditional or empirical measurements.

The Tone headline follows the Nakshatra’s traditional class. Balance adds an inward or outward emphasis, which can vary while that class remains the same. It does not decide favourability or replace the attributed activity guidance.

How calculation quality is protected

• Core calculations are deterministic: the same inputs should produce the same outputs.
• Calculation assumptions such as Lahiri sidereal conversion, the local-noon summary convention and the sunrise Vara boundary are explicit in the engine.
• Now, Day, Week and Month share one local civil-day resolver for Tithi/Paksha, Nakshatra and Nitya Yoga transition timing.
• The codebase includes automated tests across astronomy, lunar position and phase, Panchanga-related behaviour, personal-sky logic, Real Sky interactions, Moon Path and other calculation modules.
• Location is never silently replaced with a default place. The user must select a place or explicitly request device location.
• Material changes to calculation methods should be tested and reflected on this page before release.

Where differences can arise

Different Vedic traditions and software packages can use different ayanamshas, day-boundary conventions, ephemerides, rounding rules and interpretive schools. Time-zone databases and geocoding providers can also change. A boundary result that differs from another reputable tool does not automatically mean either tool is broken; the underlying assumptions should be compared first.

Real Sky is designed as a visual educational instrument rather than a precision observatory or navigation product.

Methodology statement updated: 23 September 2026.