Source google image: http://www.astrosurf.com/d_bergeron/astronomie/Bibliotheque/Chauffe_oculaire/schema%20telrad1.jpg
Schema d’une resistance electrique
Source google image: http://www.astrosurf.com/d_bergeron/astronomie/Bibliotheque/Chauffe_oculaire/schema%20telrad1.jpg