One eclipse degree, ten natal degrees
At each worldwide eclipse peak, the source calendar computes one tropical zodiac longitude: Sun for solar, Moon for lunar. A recorded birth moment supplies apparent geocentric tropical longitudes for natal Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Comparing a solar eclipse’s Sun with natal Sun is as valid geometrically as comparing it with natal Saturn; interpretation is a separate choice.
Wrap around 0° Aries
Zodiac longitude runs from 0° to just under 360°. A point at 359° and another at 1° are 2° apart, not 358° apart. The tool uses the smaller of the clockwise and counter-clockwise separations, from 0° through 180°. It then subtracts each major aspect angle: 0° conjunction, 60° sextile, 90° square, 120° trine, and 180° opposition. The absolute remainder is the orb. If it is at or below your 0.5°, 1°, or 2° threshold, the contact appears.
For example, an eclipse at 15° Leo (135° longitude) and natal Mars at 16° Scorpio (226°) are 91° apart: a square with 1° orb. Widening the threshold to 2° also includes weaker geometric approximations; it does not increase evidence for a claimed life effect.
What a missing hour changes
The natal Moon can traverse roughly a zodiac sign in a couple of days, so its exact birth degree depends strongly on the hour. Other bodies can move during a day as well, especially the Sun and Mercury near a tight cutoff. With an unknown time this lookup samples the local date at fifteen-minute intervals, excludes the Moon entirely, and calls any other match a sampled possibility. A result absent from the samples is not a proof that no between-sample match existed.
What the result cannot tell you
A worldwide solar eclipse is visible only from its geographic shadow track. A lunar eclipse is visible from locations where the Moon is above the horizon at the relevant time. A longitude aspect does not answer either visibility question. Nor does it calculate natal houses or suggest a concrete event that must happen. For local solar visibility, use the eclipse calendar’s coordinate lookup. For full chart context, use the birth-chart calculator.
Sources and calculation notes
- NASA eclipse index and NASA’s 2027 catalog independently corroborate the worldwide event sequence.
- Astronomy Engine 2.1.19 documents the eclipse searches and apparent geocentric positions used locally.
The event longitude is the Sun at a solar peak or Moon at a lunar peak. Birth-chart planetary longitudes use the same tropical coordinate convention. The five aspect names are geometric filters; meanings attributed to them are part of astrological interpretation.