Astronomical identity
Spica is the IAU proper name for Alpha Virginis Aa (HR 5056), in Virgo. The IAU component identifier avoids collapsing a multiple-star system into an unspecific conventional label.
The selected star’s calculated horizon or meridian event is a geometry result. It is not a declaration that the observer saw an object through atmosphere or terrain.
Name and historical record
Latin spica denotes an ear or spike of grain. The IAU counts Spica among names preserved from Greek antiquity; the Latin lexical sense is not a single universal mythic interpretation.
Keeping word history separate from reading avoids treating ‘grain’ as a hidden computational input.
Ptolemy’s named comparison
Ptolemy’s I.9 says ‘the so-called Spica’ is like Venus and, to a lesser degree, Mars. This compact source-specific label is present in the historical comparison dataset.
It should be read as a comparison within Ptolemy’s planetary-quality language, not as an instruction to combine an event with Venus and Mars keywords.
Use in a modern paran result
Choose Spica and one partner, then inspect whether the match joins a horizon event to a transit or two other named angles. Save the exact row before changing the tolerance, because a different tolerance can change which pairs appear.
Brady’s account supplies the modern angle-based context. A study view may put Ptolemy’s Venus/lesser-Mars comparison next to the selected row, while preserving its historical source label.
Bernadette Brady, Fixed Stars, other voices in our astrology ↗
Word origin · etymology
Latin spica.
The Latin noun denotes an ear or spike of grain. It names the star but does not itself prescribe an interpretive outcome.
How we know · epistemology
Astronomical identification; historical and interpretive records kept separate.
The IAU list attaches Spica to Alpha Virginis Aa. Ptolemy’s Venus-with-lesser-Mars likeness is a source-specific comparison, not evidence for a fixed result when a modern tool finds an angular event.
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Connected concepts
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Terms used in this explanation
These links connect subjects and terminology. They do not establish a shared historical origin.
Sources & provenance
Use the citations beside each section to distinguish a calculation convention, a historical teaching and an editorial example.