Which optical distortion increases when using parabolic mirrors with imperfections during medieval Islamic astronomical observations?

💡 Explanation

When a parabolic mirror deviates from its ideal shape, coma occurs because off-axis light rays converge at different points, creating a comet-like blur. Therefore, coma is exacerbated in imperfect medieval mirrors, rather than chromatic aberration, spherical aberration or astigmatism which stem from different optical imperfections or material properties.

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