Telescope resolution Two stars that are very close may appear to be one. The ability of a...

Telescope resolution Two stars that are very close may appear to be one. The ability of a telescope to separate their images is called its resolution. The smaller the resolution, the better a telescope’s ability to separate images in the sky. In a refracting telescope, resolution θ (see the figure) can be improved by using a lens with a larger diameter D. The relationship between θ in degrees and D in meters is given by sin θ = 1.22⋋/D, where A is the wavelength of light in meters. The largest refracting telescope in the world is at the University of Chicago. At a wavelength of A = 550 × 10−9 meter, its resolution is 0.00003769°. Approximate the diameter of the lens.

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