Measurements of the LWS beam profile suggest that it is narrower than expected and, indeed, less than diffraction theory predicts. This is not yet understood. The width varies from detector channel to detector channel: at face value, the data suggest that it can be as low as 58" and as high as 82" but it is not monotonic with wavelength. Until further observations are made and modelling has been carried out, it is impossible to say what the true beam shape is.