Word origin · etymology
Latin prefix on a geometric term.
Contra- means opposite or against; it marks equal-sized declinations on opposite sides of the celestial equator.
How we know · epistemology
Equatorial angular criterion
The comparison matches declination magnitudes across the celestial equator. Its geometry is testable, but equating it with a zodiacal opposition adds an interpretive correspondence.
Connected concepts
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.