Complex sentence: A Besselian year, named after the German mathematician and astronomer Friedrich Bessel (1784--1846), is a year of which the beginning is defined Meeus, J.: "Astronomical Algorithms", page 125.
Split into simpler sentences: A Besselian year is named after the German mathematician and astronomer Friedrich Bessel (1784--1846). Meeus Meeus, J.: "Astronomical Algorithms", page 125.