Abstract: A Galilean-type telescope system comprises three components arranged successively along the optical axis thereof. The first and the second components are single positive menisci, constituting the objective of the system and separated by an air space from the third component, which is a negative concentric meniscus forming an eyepiece of the system, all three components being concave towards the eye side of the system. The third component is a lens member cemented together from two lenses having their cemented surfaces of the same shape and equal refractive indices but different dispersion, the dispersion of the lens disposed closer to said eye side being substantially less than that of the following lens. The thickness of the air space between the second and third components complies with the relationship: ##EQU1## wherein: d.sub.x --thickness of the air space,f'.sub.1 --rear focal distance of the objective,.GAMMA.--magnification provided by the system,R.sub.