The maximum resolving power that can be obtained in practice from a telescope of a given aperture. It was established by W. R. Dawes on the basis of tests of the visibility of double stars through various apertures. It states that a pair of sixth-magnitude stars can just be seen as double by a 1-inch (25.4-mm) telescope if they are separated by 4″.56. The table gives the resolving power of various instruments based on the Dawes limit.