an objective comprising axial symmetry , at least one curved mirror and at least one lens and two intermediate images . the objective includes two refractive partial objectives and one catadioptric partial objective . the objective includes a first partial objective , a first intermediate a image , a second partial objective , a second intermediate image , and a third partial objective . at least one of the partial objectives is purely refractive . one of the partial objectives is purely refractive and one is purely catoptric .