Definition of personal equation in English:

personal equation

noun

  • The correction required in scientific observations (originally in astronomy) to compensate for the habitual inaccuracy of an individual observer; (in extended use) the component of a situation which relates to or arises from an individual's personal qualities.

Origin

Mid 19th century; earliest use found in Monthly Notices of the Royal Astronomical Society. After German Personal-Gleichung (F. W. Bessel, 1822).