Fr.: besselien, de Bessel
Besselian day number
šomâre-ye ruz-e Besseli
Besselian star constant
pâyâ-ye axtari-ye Besseli
Fr.: constante stellaire besselienne
Any of the eight quantities denoted by a, b, c, d (for → right ascension) and a', b', c', d' (for → declination) used in conjunction with → Besselian day numbers for the reduction of star's → mean catalog place.
Fr.: année besselienne
The period taken for the right ascension of the mean Sun to increase by 24 hours. The starting point is when the mean Sun's longitude is 280°, corresponding roughly to January 1. It is virtually the same as the tropical year.