A projection objective has an object surface and an image surface. The projection objective includes a plurality of optical elements arranged along an optical axis and configured so that during operation the projection objective images a pattern arranged in the object surface onto the image surface. The optical elements include a concave mirror a first deflecting mirror and a second deflecting mirror. The first deflecting mirror is tilted relative to the optical axis by a first tilt angle, t1, about a first tilt axis so that during operation the first deflecting mirror deflects light at a wavelength λ from the object surface towards the concave mirror or deflects light at λ from the concave mirror towards the image surface. The second deflecting mirror is tilted relative to the optical axis by a second tilt angle, t2, about a second tilt axis. For a pattern including a grating having a line width of 45 nm and a pitch, p, the projection objective images the pattern to the image surface such that for a first orientation of the pattern and a second orientation of the pattern a difference, ΔHV, between the imaged line width is 1.2 nm or less for 100 nm