The invention relates to a telescope optics for a telescopic observational instrument having an objective lens, having a prism erecting system and having an eyepiece lens, wherein an image of an object generated by the objective lens is located between the prism erecting system and the eyepiece lens, and wherein the objective lens, in an order starting from the object side, comprises a first lens group G1 with a positive refractive power, a second lens group G2 with a negative refractive power and a third lens group G3, and wherein the second lens group G2 is adjustable in parallel to an optical axis for focusing, and wherein at least one lens with a negative refractive power of the third lens group G3 is adjustable perpendicularly to the optical axis for changing the position of the image, and wherein the third lens group G3 has a negative refractive power.