Bessel was also an outstanding mathematician whose name became generally known through a special class of functions that have become an indispensable tool in applied mathematics, physics and engineering.
Bessel ay din ng isang natitirang dalubbilang na ang pangalan ay naging kalat sa pamamagitan ng isang espesyal na uri ng pag-andar na maging isang ganap na kasangkapan na inilapat sa matematika, physics at engineering.