Besselian year

Target entity: Besselian year
Context triple: [Friedrich Bessel, hasEponym, Besselian year]

• A. Saros cycle
  The Saros cycle is an approximately 18-year period after which nearly identical solar and lunar eclipses repeat, due to the alignment of the Earth, Moon, and Sun.
• B. Barycentric Dynamical Time
  Barycentric Dynamical Time is a relativistic time scale used in celestial mechanics and ephemerides, defined for an observer at the solar system’s barycenter to accurately model planetary and spacecraft motions.
• C. Ephemerides
  Ephemerides is a 15th-century astronomical table compiled by Regiomontanus that provided highly accurate planetary positions and became a foundational tool for navigation and astronomy in early modern Europe.
• D. Metonic cycle
  The Metonic cycle is a 19-year astronomical period after which the phases of the Moon recur on the same days of the solar year, forming the basis for many lunisolar calendars.
• E. Milanković calendar
  The Milanković calendar is a 20th-century reform of the Julian calendar, designed by Serbian scientist Milutin Milanković to more accurately align the civil year with the solar year and used by some Eastern Orthodox churches.
• F. None of above. chosen
• G. Unsure - the case is ambiguous/there is not enough information to decide.

Target entity: Besselian year
Target entity description: A Besselian year is a time interval used in astronomy, defined with respect to the Sun’s mean position relative to the stars and historically used as a reference for star catalogs and celestial coordinates.

• A. Saros cycle
  The Saros cycle is an approximately 18-year period after which nearly identical solar and lunar eclipses repeat, due to the alignment of the Earth, Moon, and Sun.
• B. Barycentric Dynamical Time
  Barycentric Dynamical Time is a relativistic time scale used in celestial mechanics and ephemerides, defined for an observer at the solar system’s barycenter to accurately model planetary and spacecraft motions.
• C. Ephemerides
  Ephemerides is a 15th-century astronomical table compiled by Regiomontanus that provided highly accurate planetary positions and became a foundational tool for navigation and astronomy in early modern Europe.
• D. Metonic cycle
  The Metonic cycle is a 19-year astronomical period after which the phases of the Moon recur on the same days of the solar year, forming the basis for many lunisolar calendars.
• E. Milanković calendar
  The Milanković calendar is a 20th-century reform of the Julian calendar, designed by Serbian scientist Milutin Milanković to more accurately align the civil year with the solar year and used by some Eastern Orthodox churches.
• F. None of above. chosen