Fixed Star Calculator

Fixed stars are distant suns that appear nearly motionless relative to the zodiac belt, unlike planets. While planets move through signs over weeks or years, fixed stars shift only about 1 degree every 72 years due to precession. When a fixed star makes a close conjunction with a planet or angle in the birth chart, it adds a powerful additional layer of meaning to that placement.

The tradition of interpreting fixed stars dates back to Babylonian astrology and was systematized by Ptolemy. Ptolemy assigned each star a "planetary nature." For example, Regulus has a Mars-Jupiter nature: combining ambition with authority. This system still forms the foundation of fixed star interpretation today. Remember that the nature of fixed stars is for classification purposes only.

How to Read Your Results

Start with the Conjunctions tab. These show fixed stars close to your natal planets via ecliptic longitude. Stars are sorted by class: Royal Stars carry the strongest influence, followed by Behenian stars, then traditional stars. A tighter orb means a stronger contact: a 0.2-degree conjunction is far more prominent than a 1.5-degree one.

Declination parallels occur when a planet and star share the same celestial declination (distance north or south of the celestial equator). Parallels act like conjunctions and are especially important for stars far from the ecliptic. For example, Sirius has a declination of -16.7 degrees and an ecliptic latitude of -39.6 degrees. Therefore Sirius's projection in ecliptic longitude (14 degrees Cancer) does not reflect its true celestial position, but a planet near -16.7 degrees declination is physically in the same celestial band as Sirius.

Parans (paranatellonta), are calculated for your specific birth latitude and require an exact birth time. A paran occurs when a star and planet are simultaneously at one of four important points (rising, setting, culmination, anti-culmination). Brady's paran method is considered the most accurate way to assess fixed star influence because it uses the star's actual position in the sky rather than its projected ecliptic longitude position.

Royal Stars

The four Royal Stars (Aldebaran, Regulus, Antares, Fomalhaut) are among the brightest stars near the ecliptic and mark the four quarters of the sky. In Persian astrology, they were considered the four Watchers (Guardians) of the heavens. They carry the strongest fixed star influence in a birth chart. Each holds a great promise, but that promise comes with a test: Aldebaran the test of integrity, Regulus avoiding revenge, Antares resisting excess, Fomalhaut not corrupting ideals.

Behenian Stars

Used in medieval talismanic tradition, the 15 Behenian stars (from the Arabic bahman meaning "root") are each associated with a specific gemstone, plant and symbol. Detailed in Agrippa's Occult Philosophy, these stars are Algol, Alcyone, Sirius, Procyon, Capella, Arcturus, Spica, Alphecca, Vega, Altair, Deneb Algedi, Pollux, Denebola, Alnilam and Regulus (Regulus belongs to both the Royal and Behenian groups).

How Tight Should the Conjunction Orb Be?

Orb varies by star magnitude. The system used in this calculator: 1st magnitude and brighter stars (like Sirius, Vega, Arcturus) use up to 2 degrees orb. 2nd magnitude stars use 1.5 degrees, 3rd magnitude uses 1 degree, and fainter stars use 0.5 degrees orb. For stars far from the ecliptic, the conjunction is based on projection so the actual effect may be weaker. In such cases, declination parallels and parans are more reliable indicators.