Speculum

Definition

A speculum is a table of astronomical and astrological data calculated for a particular horoscope. Rather than displaying placements in a circular chart, it lists technical measurements for the planets and other relevant points. Depending on the method used, these may include celestial longitude, latitude, declination, right ascension, meridian distance, semi-arc, house position, and related values.

Astrological Meaning

In traditional astrology, the speculum provides the numerical framework needed for specialized calculations, especially primary directions and some forms of mundane house analysis. It does not carry a separate symbolic meaning like a planet, sign, or aspect. Instead, its figures describe where a celestial body is situated and how it relates to the local horizon and meridian. Because different house systems or directional methods may require different measurements, the contents of a speculum can vary.

Why It Matters

A speculum allows astrologers to inspect the geometry behind a horoscope rather than relying only on the chart wheel. This can help with verifying positions, calculating directions, comparing traditional techniques, and understanding how celestial coordinates become mundane placements. Most modern software generates these values automatically, but recognizing them remains useful when studying older texts or evaluating technical work. Interpretation still depends on the planets, houses, aspects, and method being applied; the speculum is the structured data that supports that judgment.

Related Encyclopedia Entries

• Traditional Astrology
• Astrological Terminology
• Natal Chart