Does AstroNow use real astronomical calculations, or preset tables?

Real calculations. Every position on the site is computed at request time from an astronomical ephemeris — the same category of calculation used for sky maps and planetarium software — not looked up from a pre-written almanac or a static table of dates.

Why does AstroNow show geocentric positions by default?

AstroNow's daily calendar and tables show the shared sky as seen from Earth's center (geocentric positions), which do not depend on personal birth data. For the interactive chart wheel, Placidus house cusps (Ascendant, Midheaven, Houses 1–12) are calculated using latitude and longitude estimated from your selected timezone.

What is the difference between the tropical and sidereal zodiac?

The tropical zodiac (what AstroNow uses) is fixed to the seasons, with 0° Aries defined by the March equinox. The sidereal zodiac, used in Vedic astrology, is fixed to the visible background stars instead. Because the equinox slowly drifts relative to the stars, the two systems now disagree by roughly 24 degrees on where each sign begins.

How precise are the sign-change and aspect times shown?

Ingress (sign-change) and station (retrograde/direct) times are narrowed down to the minute. Exact-aspect times use the same binary-search approach down to 1-minute precision. Precision is limited by the underlying ephemeris library, not by rounding in the site's display.

Does AstroNow account for my location on Earth?

Geographic location does not affect planetary longitudes (which are geocentric and identical for all observers on Earth), but your selected timezone location is used to calculate house cusps for the interactive chart wheel and to format local event times.

Will AstroNow ever add personal birth charts?

It is not part of the primary daily view today. AstroNow is intentionally scoped to the shared, present-moment sky rather than individual birth charts. The Contact page is the right place to send feedback or feature requests.

How AstroNow Calculates Astrology Data

This page transparently explains exactly what astronomical calculations AstroNow performs, which ephemeris algorithms are used, and where the line lies between verifiable calculations and astrological interpretation.

1. How AstroNow Works

AstroNow calculates current astronomical positions and event timestamps in real time using physical ephemeris algorithms. Sourced from these precise coordinates, the service provides reference astrological information and interpretations while strictly separating mathematical facts from interpretative content.

2. What AstroNow Displays

AstroNow computes and displays positions for 14 celestial bodies and calculated points:

Sun (☉): Calculated via astronomy-engine apparent geocentric longitude. Always moves in direct motion.
Moon (☽): Calculated via astronomy-engine apparent geocentric longitude. Always moves in direct motion.
Mercury (☿): Calculated via astronomy-engine apparent geocentric longitude. Can enter retrograde motion.
Venus (♀): Calculated via astronomy-engine apparent geocentric longitude. Can enter retrograde motion.
Mars (♂): Calculated via astronomy-engine apparent geocentric longitude. Can enter retrograde motion.
Jupiter (♃): Calculated via astronomy-engine apparent geocentric longitude. Can enter retrograde motion.
Saturn (♄): Calculated via astronomy-engine apparent geocentric longitude. Can enter retrograde motion.
Uranus (♅): Calculated via astronomy-engine apparent geocentric longitude. Can enter retrograde motion.
Neptune (♆): Calculated via astronomy-engine apparent geocentric longitude. Can enter retrograde motion.
Pluto (♇): Calculated via astronomy-engine apparent geocentric longitude. Can enter retrograde motion.
North Node (☊): True North Node of the lunar orbit (Meeus astronomical series). Can enter retrograde motion.
South Node (☋): Derived as the exact opposite point of the True North Node (+180°). Can enter retrograde motion.
Lilith (M) (⚸): Mean Black Moon Lilith (mean lunar apogee = mean perigee + 180°). Always moves in direct motion.
Chiron (⚷): Analytical mean longitude approximation with annual perturbation loop. Can enter retrograde motion.

3. Source of Astronomical Data

All calculations take place locally in-process using the open-source ephemeris library astronomy-engine (version ^2.1.19). No external astrology APIs or third-party network requests are made. Algorithms automatically account for light-time correction, precession, nutation, and stellar aberration.

4. Coordinate and Zodiac System

AstroNow uses the Western tropical zodiac (where 0° Aries is defined by the March equinox). Planetary coordinates are computed as apparent geocentric ecliptic longitude (angular position from 0° to 360° as seen from Earth's center). The visitor's geographic location does not change planetary longitudes. However, for the interactive chart wheel, Placidus house cusps are calculated topocentrically using latitude and longitude estimated from the selected timezone.

5. Zodiac Positions

The ecliptic is divided into 12 equal 30° sign bands starting at Aries (0°). Sign assignment is calculated as floor(longitude / 30). Degrees and minutes are rounded to the nearest minute. When rounded minutes reach 60, the degree increments by 1, and crossing 30° visually shifts the body to the next sign.

6. Planetary Aspects

AstroNow calculates 6 aspect types between celestial bodies. The maximum allowable orb threshold is strictly 5.0° for all aspects:

Aspect Name	Symbol	Target Angle	Max Orb	Classification
Conjunction	☌	0°	±5.0°	Neutral (Major)
Sextile	⚹	60°	±5.0°	Positive (Major)
Square	□	90°	±5.0°	Challenging (Major)
Trine	△	120°	±5.0°	Positive (Major)
Opposition	☍	180°	±5.0°	Challenging (Major)
Quincunx	⚻	150°	±5.0°	Mixed (Minor)

Aspects distinguish applying (↗) (angular distance narrowing) from separating (↘). Orbs under 0.05° are marked as 🎯 Exact Peak. Conjunctions that fail to reach exactness due to planetary station or sign change are flagged as averted.

7. Moon Phases

Moon phases are calculated from the continuous Sun-Moon phase angle [0°, 360°), not from rounded illumination percentages. The four exact astronomical events — New Moon (0°), First Quarter (90°), Full Moon (180°), and Last Quarter (270°) — are pinned to 1-minute precision.

A ±12-hour proximity window around exact events governs the primary stage label, preventing UI countdown contradictions.

8. Void-of-Course Moon

The void-of-course Moon begins at the moment the Moon forms its last exact major aspect (conjunction, sextile, square, trine, opposition) with any of the other 13 tracked objects in its current sign, and ends when it enters the next sign (ingress).

9. Retrograde Motion

Retrograde motion is an apparent visual effect caused by relative orbital velocities. AstroNow measures longitudinal speed dλ/dt over a 2-hour window; if negative, the body is flagged retrograde (R). The Sun, Moon, and Mean Lilith never go retrograde.

10. Dates and Timezones

All calculations execute in UTC. Visitor timezones are detected via Intl.DateTimeFormat or manually selected. SSR provides initial server rendering, and client hydration applies local timezone formatting seamlessly.

11. Accuracy and Limitations

Event timing (ingresses, stations, aspects, phases) is refined via binary search to 1-minute precision.
Uses the Western tropical zodiac exclusively.
Planetary placements are geocentric; Placidus houses in the wheel chart use the selected timezone location.
Content is intended for personal reflection and reference.

12. Astronomy vs. Astrological Interpretation

Astronomical placements and timestamps are calculated scientific facts. Astrological meanings are traditional interpretations. Astrology is not scientifically validated and is provided for reflection and entertainment.

13. Updates and Feedback

AstroNow algorithms are continuously updated. If you spot a discrepancy or have feedback, please reach out on the Contact page.

Frequently asked questions

Does AstroNow use real astronomical calculations, or preset tables?: Real calculations. Every position on the site is computed at request time from an astronomical ephemeris — the same category of calculation used for sky maps and planetarium software — not looked up from a pre-written almanac or a static table of dates.
Why does AstroNow show geocentric positions by default?: AstroNow's daily calendar and tables show the shared sky as seen from Earth's center (geocentric positions), which do not depend on personal birth data. For the interactive chart wheel, Placidus house cusps (Ascendant, Midheaven, Houses 1–12) are calculated using latitude and longitude estimated from your selected timezone.
What is the difference between the tropical and sidereal zodiac?: The tropical zodiac (what AstroNow uses) is fixed to the seasons, with 0° Aries defined by the March equinox. The sidereal zodiac, used in Vedic astrology, is fixed to the visible background stars instead. Because the equinox slowly drifts relative to the stars, the two systems now disagree by roughly 24 degrees on where each sign begins.
How precise are the sign-change and aspect times shown?: Ingress (sign-change) and station (retrograde/direct) times are narrowed down to the minute. Exact-aspect times use the same binary-search approach down to 1-minute precision. Precision is limited by the underlying ephemeris library, not by rounding in the site's display.
Does AstroNow account for my location on Earth?: Geographic location does not affect planetary longitudes (which are geocentric and identical for all observers on Earth), but your selected timezone location is used to calculate house cusps for the interactive chart wheel and to format local event times.
Will AstroNow ever add personal birth charts?: It is not part of the primary daily view today. AstroNow is intentionally scoped to the shared, present-moment sky rather than individual birth charts. The Contact page is the right place to send feedback or feature requests.