Airy disc

The Airy disc is the bright central maximum in the diffraction pattern of a single hole, random tiny holes, or objects (water droplets, pollen grains etc.) of uniform size. The telescope image above, is not the disc of a star. Distant stars appear as points of light (single pixels in a digital image). The apparent image of the star is the Airy disc - the central maximum of the diffraction pattern of the telescope aperture. The first ring can be seen faintly.

Diffraction effects; pollen halos, corona and iridescence, are seen in the atmosphere.

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