Bandwidth smearing

Bandwidth smearing is a type of chromatic aberration in the image of a celestial body observed using an astronomical interferometer. It is caused by the range of radio frequencies used in the observation, where, in Fourier terms, different frequencies capture slightly different spatial details of the object’s shape. This leads to a blurred or stretched appearance in the final image, often with elongated features pointing outward. In radio astronomy, this effect can be reduced by using higher spectral resolution or adjusting the image reconstruction process to account for these differences.